Online Etymology Dictionary

sweat (n.): Old English swat "perspiration, moisture exuded from the skin," also "labor, that which causes sweat," from Proto-Germanic *swaitaz "sweat" (source also of Old Saxon, Old Frisian swet, Old Norse sveiti, Danish sved "sweat," Swedish svett, Middle Dutch sweet, Dutch zweet, Old High German sweiz, German Schweiß), from PIE *sweid- (2) "to sweat" (source also of Sanskrit svedah "sweat," Avestan xvaeda- "sweat," Greek hidros "sweat, perspiration," Latin sudor, Lettish swiedri, Welsh chwys "sweat").

A widespread set of Slavic words (Polish, Russian pot "sweat") is from Old Church Slavonic potu, related to peku "heat," cognate with Latin coquere.

The Old English noun became Middle English swote, but later altered to the current form under the influence of the verb. Sweat of (one's) brow as a symbol of toil is from Gen. iii:19. Sweat equity is from 1968. Colloquial no sweat "no problem" attested from 1963.
sweat-bee (n.): 1870, American English, from sweat (n.) + bee (n.).
sweater (n.): "woolen vest or jersey, originally worn in rowing," 1882, from earlier sweaters "clothing worn to produce sweating and reduce weight" (1828), plural agent noun from sweat (v.). As a fashion garment, attested from 1925. Earlier it meant "one who works hard" (1520s). Sweater girl is attested from 1940; Lana Turner (1920-1995) was the first, from her appearance in the film "They Won't Forget" (1937).
sweatpants (n.): also sweat-pants, 1946, from sweat (v.) + pants (n.).
sweatshirt (n.): also sweat-shirt, 1921, from sweat (v.) + shirt. Related: Sweatshirted.
sweatshop (n.): also sweat-shop, 1892, from sweat (v.) + shop (n.). The verb sweat is attested from 1879 in the sense "employ (someone) in hard work for low wages," and compare sweater "one who exacts wages at very low prices" (1846).
sweaty (adj.): late 14c., "causing sweat;" 1580s, "soaked with sweat," from sweat (n.) + -y (2). Related: Sweatiness.
Swede (n.): "native of Sweden," 1610s, from Low German, from Middle Low German Swede, from a source akin to Old English Sweoðeod, literally "Swede-people," from Sweon (plural) "Swedes" (Old Norse, Old Swedish Sviar), called by the Romans Suiones, probably from Proto-Germanic *sweba "free, independent," or else from *geswion "kinsman."
Sweden: c. 1600, originally in Scottish (Swethin, Swadne, etc.), from Middle Dutch Sweden, probably a dative plural of Swede (earlier in English Sweden was used of the people and until 17c. Swedeland was the English name of the country). In Old English, the country was Sweoland or Sweorice (compare Old Norse sviariki, source of Swedish Sverige). Ultimately named for the original inhabitants (see Swede).
Swedenborgian: 1791, from name of Emanuel Svedberg, Swedish mystic and religious philosopher (1668-1772). His followers organized 1788 as The New Church.
Swedish (adj.): c. 1600, from Swede + -ish. Similar formation in Dutch Zweedsch, German Schwedisch. Related: Swedishness. As a language name from c. 1600. The candy Swedish fish attested by that name by 1983.
sweep (v.): early 14c., "make clean by sweeping with a broom;" mid-14c., "perform the act of sweeping," of uncertain origin, perhaps from a past tense form of Middle English swope "sweep," from Old English swapan "to sweep" (transitive & intransitive); see swoop (v.), or perhaps from a Scandinavian source. Related: Swept; sweeping.

From late 14c. as "hasten, rush, move swiftly and strongly;" also "collect by sweeping." From c. 1400 in transitive sense "drive quickly, impel, move or carry forward by force;" mid-15c. as "clear (something) away." Meaning "win all the events" is 1960, American English. Sense of "pass systematically over in search of something" is from 1966. To sweep (someone) off (his or her) feet "affect with infatuation" is from 1913.
sweep (n.): mid-13c., "stroke, force," from sweep (v.). Meaning "act of sweeping" is from 1550s. From 1670s as "range, extent of a continued motion." In reference to police or military actions, it is attested from 1837. Sense of "a winning of all the tricks in a card game" is from 1814 (see sweepstakes); extended to other sports by 1960. Meaning "rapid survey or inspection" is from 1966. As a shortened form of chimney-sweeper, first attested 1796.
sweeper (n.): 1520s, agent noun from sweep (v.). As a position in soccer (association football) by 1964.
sweepstakes (n.): "prize won in a race or contest," 1773, from Middle English swepestake "one who sweeps or wins all the stakes in a game" (late 14c. as a surname or nickname; late 15c. as the name of one of the King's ships), from swepen "to sweep" (see sweep (v.)) + stake (n.2). Meaning "any race for stakes contributed" is from 1862.
sweet (n.): c. 1300, "something sweet to the taste," also "beloved one," from sweet (adj.); the specific meaning "candy drop" is 1851 (earlier sweetie, 1721). Meaning "one who is dear to another" is from 14c. Old English swete (n.) meant "sweetness."
sweet (adj.): Old English swete "pleasing to the senses, mind or feelings; having a pleasant disposition," from Proto-Germanic *swotja- (source also of Old Saxon swoti, Old Frisian swet, Swedish söt, Danish sød, Middle Dutch soete, Dutch zoet, Old High German swuozi, German süß), from PIE root *swad- "sweet, pleasant" (Sanskrit svadus "sweet;" Greek hedys "sweet, pleasant, agreeable," hedone "pleasure;" Latin suavis "pleasant" (not especially of taste), suadere "to advise," properly "to make something pleasant to"). Words for "sweet" in Indo-European languages typically are used for other sense as well and in general for "pleasing."
Then come kiss me, sweet-and-twenty!
Youth's a stuff will not endure.
["Twelfth Night"]
Also "being in a sound or wholesome state" (mid-13c.), and, of water, "fresh, not salt" (late Old English). As an intensifier from 1958. Sweet in bed (c. 1300) was the equivalent of modern "good in bed." To be sweet on someone is first recorded 1690s. Sweet sixteen first recorded 1767. Sweet dreams as a parting to one going to sleep is attested from 1897, short for sweet dreams to you, etc. Sweet-and-sour in cookery is from 1723 and not originally of oriental food. Sweet nothings "sentimental trivialities" is from 1900. Sweet spot is from 1976, first in reference to tennis rackets. Sweet corn is from 1640s.
Sweet Adeline: female barbershop singing group member, 1947, from the name of a popular close harmony song by Richard Armstrong & Harry Gerard, "You're the Flower of my Heart, Sweet Adeline" (1903).
sweet tooth (n.): "fondness for sugary stuff," late 14c., from sweet (adj.) + tooth in the sense of "taste, liking" (see toothsome).
sweet-briar (n.): "eglantine," 1530s, from sweet (adj.) + briar (n.).
sweet-grass (n.): 1570s, from sweet (adj.) + grass (n.). Perhaps so called for the fondness of cattle for it.
sweet-pea (n.): 1732, from sweet (adj.) + pea (n.).
sweet-talk (v.): Sweet-talk, 1935, from noun phrase; see sweet (adj.) + talk (n.). Earliest usages seem to refer to conversation between black and white in segregated U.S.
"I ain' gonna stay heah no longah. Don' nevah keer, ef I do git cotched--or die. Tha's bettah than to stay heah an' listen to Maw Haney sweet-talk the white folks, whilst they drives us clean to the grave. ..." ["The Crisis," July 1935]
Latin had suaviloquens, literally "sweet-spoken."
sweetbread (n.): "pancreas of an animal used as food" 1560s, from sweet (adj.); the -bread element may be from Old English bræd "flesh."
sweeten (v.): 1550s (intransitive), from sweet (adj.) + verbal ending -en (1). Transitive sense ("become sweet") is from 1620s. The Middle English form of the verb was simply sweet, from Old English swetan. Related: Sweetened; sweetening.
sweetener (n.): 1640s, agent noun from sweeten (v.).
sweetheart (n.): late 13c. as a form of address, 1570s as a synonym for "loved one;" from sweet (adj.) + heart (n.). As an adjective, with reference to labor contracts, it is attested from 1959.
sweetie (n.): 1721, "lollipop;" 1778, "lover, sweetheart," from sweet (n.) + -ie.
sweetly (adv.): Old English swetlice; see sweet (adj.) + -ly (2).
sweetmeat (n.): "a sweet thing to eat," Old English swete mete; see sweet (adj.) + meat (n.).
sweetness (n.): Old English swetnes; see sweet (adj.) + -ness.
swell (n.): c. 1200, "a morbid swelling," from swell (v.). In reference to a rise of the sea, it is attested from c. 1600; of music, by 1803. The meaning "wealthy, elegant person" is first recorded 1786, connected to the now-obsolete sense "pompousness, arrogance" (1724), both from the notion of "puffed-up" demeanor or behavior.
swell (v.): Old English swellan "grow or make bigger" (past tense sweall, past participle swollen), from Proto-Germanic *swelnan (source also of Old Saxon swellan, Old Norse svella, Old Frisian swella, Middle Dutch swellen, Dutch zwellen, Old High German swellan, German schwellen), of unknown origin. Of emotions from late 14c., of music from 1749. Related: swelled; swollen; swelling.
swell (adj.): "fashionably dressed or equipped," 1810, from swell (n.) in the "stylish person" sense. As "good, excellent," by 1897; as a stand-alone expression of satisfaction it is recorded from 1930 in American English.
swelling (n.): "tumor, morbid enlargement," Old English; verbal noun from swell (v.).
swelter (v.): c. 1400, "faint with heat," frequentative of swelten "be faint (especially with heat)," late 14c., from Old English sweltan "to die, perish," from Proto-Germanic *swiltan- (source also of Old Saxon sweltan "to die," Old Norse svelta "to put to death, starve," Gothic sviltan "to die"), perhaps originally "to burn slowly," hence "to be overcome with heat or fever," from PIE root *swel- (2) "to shine, beam" (see Selene). From the same ancient root comes Old English swelan "to burn." For specialization of words meaning "to die," compare starve. Related: Sweltered; sweltering.
swelter (n.): "a sweltering condition," 1851, from swelter (v.).
sweltering (adj.): "oppressively hot" (of weather, seasons), 1590s, present participle adjective from swelter (v.). Related: Swelteringly.
sweltry (adj.): 1570s, for *sweltery, from swelter (v.) + -y (2).
swept: past participle of sweep (v.).
swerve (v.): c. 1200, "to depart, go make off; turn away or aside;" c. 1300, "to turn aside, deviate from a straight course;" in form from Old English sweorfan "to rub, scour, file away, grind away," but sense development is difficult to trace. The Old English word is from Proto-Germanic *swerb- (cf Old Norse sverfa "to scour, file," Old Saxon swebran "to wipe off"), from PIE root *swerbh- "to turn; wipe off." Cognate words in other Germanic languages (Old Frisian swerva "to creep," Middle Dutch swerven "to rove, roam, stray") suggests the sense of "go off, turn aside" might have existed in Old English, though unrecorded. Related: Swerved; swerving.
swerve (n.): 1741, from swerve (v.).
swift (adj.): Old English swift "moving quickly," perhaps originally "turning quickly," from Proto-Germanic swip- (see swivel (n.)). Related: Swiftly; swiftness.
swift (n.): type of bird (several species of the family Cypselidæ, resembling swallows), 1660s, from swift (adj.) in reference to its swift flight. Regarded as a bird of ill-omen, if not downright demonic, probably for its shrill cry. The name earlier had been given to several small fast lizards (1520s).
swig (n.): 1540s, "a drink, liquor," later "big or hearty drink of liquor" (1620s), of unknown origin.
swig (v.): 1650s, from swig (n.). Related: Swigged; swigging.
swill (v.): Old English swilian, swillan "to wash out, gargle," probably from Proto-Germanic *swil-, related to the root of swallow (v.). Meaning "drink greedily" is from 1530s. Related: Swilled; swilling.
swill (n.): "liquid kitchen refuse fed to pigs," 1550s, from swill (v.).
swim (n.): 1540s, "the clear part of any liquid" (above the sediment), from swim (v.). Meaning "part of a river or stream frequented by fish" (and hence fishermen) is from 1828, and is probably the source of the figurative meaning "the current of the latest affairs or events" (as in in the swim "on the inside, involved with current events," 1869). Meaning "act of swimming" is from 1764.
swim (v.): Old English swimman "to move in or on the water, float" (class III strong verb; past tense swamm, past participle swummen), from Proto-Germanic *swimjan (source also of Old Saxon and Old High German swimman, Old Norse svimma, Dutch zwemmen, German schwimmen), from PIE root *swem- "to be in motion."

The root is sometimes said to be restricted to Germanic, but according to OED possible cognates are Welsh chwyf "motion," Old Irish do-sennaim "I hunt," Lithuanian sundyti "to chase." For the usual Indo-European word, see natatorium. Transitive sense of "cross by swimming" is from 1590s. Sense of "reel or move unsteadily" first recorded 1670s; of the head or brain, from 1702. Figurative phrase sink or swim is attested from mid-15c., in early use often with reference to ordeals of suspected witches.