Online Etymology Dictionary

slim (v.): 1808, "to scamp one's work, do carelessly or superficially," from slim (adj.). Meaning "to make slim" (a garment, etc.) is from 1862; meaning "reduce (one's) weight" is from 1930. Related: Slimmed; slimming.
slime (n.): Old English slim "slime," from Proto-Germanic *slimaz (source also of Old Norse slim, Old Frisian slym, Dutch slijm "slime, phlegm," German Schleim "slime"), probably related to Old English lim "birdlime; sticky substance," from PIE root *(s)lei- "slimy, sticky, slippery" (source also of Sanskrit linati "sticks, stays, adheres to; slips into, disappears;" Russian slimak "snail;" Old Church Slavonic slina "spittle;" Old Irish sligim "to smear," leinam "I follow," literally "I stick to;" Welsh llyfn "smooth;" Greek leimax "snail," limne "marsh, pool, lake," alinein "to anoint, besmear;" Latin limus "slime, mud, mire," linere "to daub, besmear, rub out, erase"). As an insult to a person from mid-15c. Slime-mold is from 1880.
slime (v.): "to cover with slime," 1620s, from slime (n.). Related: Slimed; sliming.
slimming (adj.): "producing an appearance of thinness," 1925, present participle adjective from slim (v.).
slimnastics (n.): 1967 (with an isolated use from 1959), from slim (adj.) + ending abstracted from gymnastics.
slimy (adj.): late 14c., "covered with slime; of the nature of slime," from slime (n.) + -y (2). Similar formation in Middle Dutch slimich, Dutch slijmig, German schleimig. Figurative sense of "morally repulsive" is first attested 1570s. Related: Slimily; sliminess.
sling (v.): c. 1200, "to knock down" using a sling, later "to throw" (mid-13c.), especially with a sling, from Old Norse slyngva, from Proto-Germanic *slingwanan (source also of Old High German slingan, German schlingen "to swing to and fro, wind, twist;" Old English slingan "to creep, twist;" Old Frisian slinge, Middle Dutch slinge, Old High German slinga, German Schlinge "sling;" Middle Swedish slonga "noose, knot, snare"), from PIE *slengwh "to slide, make slide; sling, throw." Meaning "to hang from one point to another" (as a hammock) is from 1690s. Related: Slung; slinging.
sling (n.2): sweetened, flavored liquor drink, 1807, American English, of unknown origin; perhaps literally "to throw back" a drink (see sling (v.)), or from German schlingen "to swallow."
sling (n.1): c. 1300, "implement for throwing stones," from an unidentified continental Germanic source (such as Middle Low German slinge "a sling"); see sling (v.). The notion probably is of a sling being twisted and twirled before it is thrown. Sense of "loop for lifting or carrying heavy objects" first recorded early 14c. Meaning "piece of cloth tied around the neck to support an injured arm" is first attested 1720.
sling (n.3): "act of throwing," 1520s, from sling (v.).
slinger (n.): "soldier armed with a sling," late 14c., agent noun from sling (v.).
slingshot (n.): 1849, from sling (v.) + shot (n.). As a verb, from 1969. The piece of stone or metal hurled from it is a sling-stone (late 14c.). A slung-shot (1848) was a rock wrapped in a sling, used as a weapon by roughs and criminals.
slink (v.): Old English slincan "to creep, crawl" (of reptiles), from Proto-Germanic *slinkan (source also of Swedish slinka "to glide," Dutch slinken "to shrink, shrivel;" related to sling (v.)). Of persons, attested from late 14c. Related: Slinked; slinking.
slinky (adj.): "sinuous and slender," of women or clothes, 1921, from slink + -y (2). Related: Slinkily; slinkiness. As a proprietary name (with capital from S-) for a coil of spring marketed as a toy, 1948, by James Industries Inc., Philadelphia, U.S.A.
slip (n.1): mid-15c., "edge of a garment;" 1550s, "narrow strip," probably from Middle Low German or Middle Dutch slippe "cut, slit," possibly related to Old English toslifan "to split, cleave." Sense of "narrow piece of paper" (as in pink slip) in 1680s.
slip (n.2): in various senses from slip (v.). Meaning "act of slipping" is from 1590s. Meaning "mistake, minor fault, blunder" is from 1610s. Sense of "woman's sleeveless garment" (1761) is from notion of something easily slipped on or off (compare sleeve). To give (someone) the slip "escape from" is from 1560s. Meaning "landing place for ships" is mid-15c.; more technical sense in ship-building is from 1769. Slip of the tongue is 1725 (from Latin lapsus linguae); slip of the pen (Latin lapsus calami) is 1650s.
slip (n.3): "potter's clay," mid-15c., "mud, slime," from Old English slypa, slyppe "slime, paste, pulp, soft semi-liquid mass," related to slupan "to slip" (see sleeve).
slip (n.4): "sprig or twig for planting or grafting, small shoot," late 15c., of uncertain origin. Compare Middle Dutch slippe, German schlippe, schlipfe "cut, slit, strip." Hence "young person of small build" (1580s, as in a slip of a girl); see slip (n.1).
slip (v.): early 14c., "to escape, to move softly and quickly," from an unrecorded Old English word or cognate Middle Low German slippen "to glide, slide," from Proto-Germanic *slipan (source also of Old High German slifan, Middle Dutch slippen, German schleifen "to glide, slide"), from PIE *sleib-, from root *(s)lei- "slimy, sticky, slippery" (see slime (n.)).

From mid-14c. with senses "lose one's footing," "slide out of place," "fall into error or fault." Sense of "pass unguarded or untaken" is from mid-15c. That of "slide, glide" is from 1520s. Transitive sense from 1510s; meaning "insert surreptitiously" is from 1680s. Related: Slipped; slipping. To slip up "make a mistake" is from 1855; to slip through the net "evade detection" is from 1902. To let (something) slip originally (1520s) was a reference to hounds on a leash; figurative use "allow to escape through carelessness" is from 1540s.
slipknot (n.): also slip-knot, 1650s, from slip (v.) + knot (n.). One which easily can be "slipped" or undone by pulling on the loose end of the last loop.
slippage (n.): 1850, "act of slipping," from slip (v.) + -age.
slipper (n.): type of loose, light indoor footwear, late 15c., agent noun from slip (v.), the notion being of a shoe that is "slipped" onto the foot. Old English had slypescoh "slipper," literally "slip-shoe."
slippery (adj.): "having a slippery surface," c. 1500, from Middle English sliper (adj.) "readily slipping," from Old English slipor "slippery, having a smooth surface" (see slip (v.)) + -y (2). Metaphoric sense of "deceitful, untrustworthy" is first recorded 1550s. Related: Slipperiness. In a figurative sense, slippery slope is first attested 1844. Slippery elm (1748) so called for its mucilaginous inner bark.
slipshod (adj.): 1570s, "wearing slippers or loose shoes," from slip (v.) + shod "wearing shoes." Sense of "slovenly, careless" is from 1815, probably from the notion of appearing like one in slippers, or whose shoes are down at the heels.
slipstream (n.): also slip-stream, 1913, from slip (n.2) + stream (n.).
slit (v.): c. 1200, from or related to Old English slitan "to slit, tear, split, rend to pieces; bite, sting; back-bite," from Proto-Germanic *slitan (source also of Old Saxon slitan, Old Frisian slita, Old Norse slita, Middle Low German and Middle Dutch sliten, Dutch slijten, Old High German slizan, German schleißen "to slit"). A more violent verb in Old English than after, as in slitcwealm "death by rending." Slit skirt is attested from 1913.A slitting-mill (1660s) cut iron plates into thin rods for making nails, etc.
slit (n.): mid-13c., "long cut or rent (in clothes), incision," from slit (v.). Slang sense of "vulva" is attested from 1640s. Old English had slit (n.) with a sense of "a rending, bite; backbiting."
slither (v.): early 15c., variant of Middle English slidder "to slip, slide," from Old English slidrian "to slip, slide on a loose slope," a frequentative form of slidan "to slide" (see slide (v.)). For spelling change, compare gather. Meaning "to walk in a sliding manner" is attested from 1848. In reference to reptile motion, attested from 1839. Related: Slithered; slithering.
slither (n.): "slithering movement," 1861, from slither (v.).
sliver (n.): "splinter of wood," late 14c., from obsolete verb sliven "to split, cleave," from Old English toslifan "to split, cleave" (see sleave).
Sloane Square: neighborhood near Chelsea in London, named for Sir Hans Sloane who purchased the manor of Chelsea in 1712 and whose collections contributed to the British Museum. Previous to development the place was known as Great Bloody Field ["Oxford Dictionary of London Place Names"]. Sloane Ranger attested from 1975, with a play on Lone Ranger.
slob (n.): 1780, "mud, muddy land," from Irish slab "mud, mire dirt," itself probably borrowed from English slab "muddy place" (c. 1600), from a Scandinavian source (compare Icelandic slabb "sludge"). The meaning "untidy person" is first recorded 1887, from earlier expressions such as slob of a man (1861).
slobber (v.): c. 1400, probably of imitative origin; compare Frisian slobberje "to slurp," Middle Low German slubberen "slurp," Middle Dutch overslubberen "wade through a ditch." Related: Slobbered; slobbering. As noun from c. 1400 as "mud, slime," 1755 as "saliva." Congreve has slabber (v.), from Middle Dutch slabberen.
slobbery (adj.): late 14c., "muddy," from slobber + -y (2).
sloe (n.): fruit of the blackthorn, Old English slah (plural slan), from Proto-Germanic *slaikhwon (source also of Middle Dutch sleeu, Dutch slee, Old High German sleha, German Schlehe), from PIE *sleie- "blue, bluish, blue-black" (see livid).

The vowel has been influenced by that in the old plural form, which according to OED persisted into the 17c. Scottish slae preserves the older vowel. Sloe-eyed is attested from 1804; sloe gin first recorded 1878.
slog (v.): 1824, "hit hard," probably a variant of slug (v.3) "to strike." Sense of "walk doggedly" first recorded 1872. Related: Slogged; slogger; slogging.
slog (n.): 1846, "a hard hit," from slog (v.). Sense of "spell of hard work" is from 1888.
slogan (n.): 1670s, earlier slogorne (1510s), "battle cry," from Gaelic sluagh-ghairm "battle cry used by Scottish Highland or Irish clans," from sluagh "army, host, slew," from Celtic and Balto-Slavic *slough- "help, service." Second element is gairm "a cry" (see garrulous). Metaphoric sense of "distinctive word or phrase used by a political or other group" is first attested 1704.
sloganeer (v.): 1941, from noun (1922), from slogan + -eer. Earlier verb was sloganize (1909). Related: Sloganeering.
sloop (n.): "small fore and aft rigged vessel with one mast, generally carrying a jib, fore-stay sail, mainsail, and gaff-topsail," 1620s, from Dutch sloep "a sloop;" probably from French chaloupe, from Old French chalupe "small, sloop-rigged vessel," which is perhaps related to English shallop [OED]. But according to Barnhart and Watkins the Dutch word might simply be from Middle Dutch slupen "to glide," from PIE *sleubh- (see sleeve). In old military use, a small ship of war carrying guns on the upper deck only (1670s).
slop (n.): c. 1400, "mudhole," probably from Old English -sloppe "dung" (in plant name cusloppe, literally "cow dung"), related to slyppe "slime" (see slip (v.)). Meaning "semiliquid food" first recorded 1650s; that of "refuse liquid of any kind, household liquid waste" (usually slops) is from 1815. Meaning "affected or sentimental material" is from 1866.
slop (v.): "to spill carelessly" (transitive), 1550s, from slop (n.1). Intransitive sense from 1746. Related: Slopped; slopping.
slop (n.2): late 14c., "loose outer garment," probably from Middle Dutch slop, of uncertain origin, corresponding to words in Old Norse and perhaps in Old English. Sense extended generally to "clothing, ready-made clothing" (1660s), usually in plural slops. Hence, also, slop-shop "shop where ready-made clothes are sold" (1723).
slope (v.): 1590s, "go in an oblique direction," from earlier adjective meaning "slanting" (c. 1500), probably from Middle English aslope (adv.) "on the incline" (late 15c.), from Old English *aslopen, past participle of aslupan "to slip away," from a- "away" + slupan "to slip" (see sleeve). From 1709 as "to be in a slanting position;" transitive sense "place in a slanting position" is from c. 1600. Related: Sloped; sloping.
slope (n.): 1610s, "inclination," from slope (v.). Meaning "an incline, a slant (of ground)" is from 1620s. Derogatory slang meaning "Oriental person" is attested from 1948.
sloppy (adj.): 1727, "muddy," from slop (n.1) + -y (2). Meaning "loose, ill-fitting, slovenly" is first recorded 1825, influenced by slop (n.2). Related: Sloppily; sloppiness. Sloppy Joe was originally "loose-fitting sweater worn by girls" (1942); as a name for a kind of spiced hamburger, it is attested from 1961.
slosh (n.): 1814, "slush, sludge, a watery mess," probably a blend of slush and slop (n.1) in its Middle English sense of "muddy place."
slosh (v.): "to splash about in mud or wet," 1844, from slosh (n.). Meaning "to pour carelessly" is recorded from 1875. Related: Sloshed; sloshing.
sloshed (adj.): "drunk," c. 1900, colloquial, past participle adjective from slosh (v.).
slot (n.2): "bar or bolt used to fasten a door, window, etc.," c. 1300, from Middle Dutch or Middle Low German slot (compare Old Norse slot, Old High German sloz, German Schloss "bolt, bar, lock, castle;" Old Saxon slutil "key," Dutch slot "a bolt, lock, castle"), from Proto-Germanic stem *slut- "to close" (source also of Old Frisian sluta, Dutch sluiten, Old High German sliozan, German schliessen "to shut, close, bolt, lock"), from PIE root *klau- "hook, peg" (source also of Greek kleis "key;" Latin claudere "to shut, close," clavis "key," clavus "nail;" see close (v.)). Wooden pegs seem to have been the original keys.