Online Etymology Dictionary

wasted (adj.): late 14c., "enfeebled," past participle adjective from waste (v.). Slang meaning "intoxicated" is from 1950s.
wasteful (adj.): early 14c., "destructive," from waste (n.) + -ful. Meaning "lavish" is from mid-15c. Related: Wastefully; wastefulness.
wasteland (n.): 1825 as one word, from waste (adj.) + land (n.). Figurative sense is attested from 1868. Eliot's poem is from 1922.
April is the cruellest month, breeding
Lilacs out of the dead land, mixing
Memory and desire, stirring
Dull roots with spring rain.
wastewater (n.): also waste-water, mid-15c., from waste (adj.) + water (n.1).
wastrel (n.): "spendthrift, idler," 1847, from waste (v.) + pejorative suffix -rel. Earlier "something useless or imperfect" (1790).
wat (n.): Thai Buddhist temple, said to be from Sanskrit vata "enclosure, grove."
watch (v.): Old English wæccan "keep watch, be awake," from Proto-Germanic *wakjan, from PIE *weg- (2) "to be strong, lively;" essentially the same word as Old English wacian "be or remain awake" (see wake (v.)); perhaps a Northumbrian form of it. Meaning "be vigilant" is from c. 1200. That of "to guard (someone or some place), stand guard" is late 14c. Sense of "to observe, keep under observance" is mid-15c. Related: Watched; watching.
watch (n.): Old English wæcce "a watching, state of being or remaining awake, wakefulness;" also "act or practice of refraining from sleep for devotional or penitential purposes;" from wæccan (see watch (v.)). From c. 1200 as "one of the periods into which the night is divided," in reference to ancient times translating Latin vigilia, Greek phylake, Hebrew ashmoreth.
The Hebrews divided the night into three watches, the Greeks usually into four (sometimes five), the Romans (followed by the Jews in New Testament times) into four. [OED]

On þis niht beð fowuer niht wecches: Biforen euen þe bilimpeð to children; Mid-niht ðe bilimpeð to frumberdligges; hanecrau þe bilimpeð þowuene men; morgewile to alde men. [Trinity Homilies, c. 1200]
From mid-13c. as "a shift of guard duty; an assignment as municipal watchman;" late 13c. as "person or group obligated to patrol a town (especially at night) to keep order, etc." Also in Middle English, "the practice of remaining awake at night for purposes of debauchery and dissipation;" hence wacches of wodnesse "late-night revels and debauchery." The alliterative combination watch and ward preserves the old distinction of watch for night-time municipal patrols and ward for guarding by day; in combination, they meant "continuous vigilance."

Military sense of "military guard, sentinel" is from late 14c. General sense of "careful observation, watchfulness, vigilance" is from late 14c.; to keep watch is from late 14c. Meaning "period of time in which a division of a ship's crew remains on deck" is from 1580s. The meaning "small timepiece" is from 1580s, developing from that of "a clock to wake up sleepers" (mid-15c.).
watch-chain (n.): 1739, from watch (n.) in the "timepiece" sense + chain (n.).
watch-work (n.): 1660s, from watch (n.) in the "timepiece" sense + work (n.).
watchdog (n.): also watch-dog, c. 1600, from watch (v.) + dog (n.). Figurative sense is attested by 1845.
watcher (n.): late 14c. (early 13c. as a surname), agent noun from watch (v.).
watchful (adj.): c. 1500, waccheful, from watch (v.) + -ful. Related: Watchfulness.
watchmaker (n.): 1620s, from watch (n.) in the "timepiece" sense + maker.
watchman (n.): also watch-man, c. 1400, "guard, sentinel, lookout" (late 12c. as a surname), figuratively "guardian, protector" (mid-15c.), from watch (n.) + man (n.). Also "person characterized by wakefulness" (mid-15c.).
watchtower (n.): also watch-tower, 1540s, from watch (v.) + tower (n.).
watchword (n.): also watch-word, c. 1400, "password," from watch (n.) in the military sense of "period of standing guard duty" + word (n.). In the sense of "motto, slogan" it dates from 1738.
water (n.1): Old English wæter, from Proto-Germanic *watar (source also of Old Saxon watar, Old Frisian wetir, Dutch water, Old High German wazzar, German Wasser, Old Norse vatn, Gothic wato "water"), from PIE *wod-or, from root *wed- (1) "water, wet" (source also of Hittite watar, Sanskrit udrah, Greek hydor, Old Church Slavonic and Russian voda, Lithuanian vanduo, Old Prussian wundan, Gaelic uisge "water;" Latin unda "wave").

To keep (one's) head above water in the figurative sense is recorded from 1742. Water cooler is recorded from 1846; water polo from 1884; water torture from 1928. Linguists believe PIE had two root words for water: *ap- and *wed-. The first (preserved in Sanskrit apah as well as Punjab and julep) was "animate," referring to water as a living force; the latter referred to it as an inanimate substance. The same probably was true of fire (n.).
water (v.): Old English wæterian "moisten, irrigate, supply water to; lead (cattle) to water;" from water (n.1). Meaning "to dilute" is attested from late 14c.; now usually as water down (1850). To make water "urinate" is recorded from early 15c. Related: Watered; watering.
water (n.2): measure of quality of a diamond, c. 1600, from water (n.1), perhaps as a translation of Arabic ma' "water," which also is used in the sense "lustre, splendor."
water-closet (n.): "privy with a waste-pipe and means to carry off the discharge by a flush of water," 1755, from water (n.1) + closet (n.).
water-ice (n.): "sugared water, flavored and frozen," 1818, from water (n.1) + ice (n.).
water-lily (n.): 1540s, from water (n.1) + lily (n.).
water-moccasin (n.): type of snake in the U.S. South, 1821, from water (n.1) + moccasin (q.v.).
water-pipe (n.): c. 1400, "conduit for water," from water (n.1) + pipe (n.1). The smoking sense is first attested 1824.
water-ski (n.): 1931, from water (n.1) + ski (n.). As a verb from 1953.
water-table (n.): "level of saturated ground," 1879, from water (n.1) + table (n.).
water-wheel (n.): c. 1400, from water (n.1) + wheel (n.).
waterbed (n.): also water-bed, 1610s, "a bed on board a ship," from water (n.1) + bed (n.). As a water-tight mattress filled with water, it is recorded from 1844, originally for invalids to prevent bedsores. Reinvented c. 1970 as a stylish furnishing.
waterboard (n.): 1610s (n.), "gutter," from water (n.1) + board (n.1). Waterboarding as the name of a type of torture is from 2005, but the practice is older.
watercolor (n.): also water-color, 1590s, "pigment that dissolves in water," from water (n.1) + color (n.). Meaning "picture painted in watercolors" is attested from 1854.
watercourse (n.): also water-course, c. 1500, from water (n.1) + course (n.).
watercress (n.): also water-cress, c. 1300, from water (n.1) + cress. Compare Middle Low German, Middle Dutch waterkerse, German wasserkresse. It grows in or near streams.
waterfall (n.): Old English wætergefeall; see water (n.1) + fall (n.). The modern English word is perhaps a re-formation from c. 1500. Similar formation in German wasserfall, Old Norse vatnfall.
Waterford: city in southeastern Ireland; 1783 in reference to a type of glassware manufactured there.
waterfowl (n.): early 14c., from water (n.1) + fowl (n.). Similar formation in Old High German wazzarvogel, Dutch watervogel.
waterfront (n.): also water-front, 1834, American English, from water (n.1) + front (n.). To cover the waterfront "deal with thoroughly" is attested from 1913; I Cover the Waterfront was a 1932 best-seller by San Diego newspaperman Max Miller.
watergate (n.): mid-14c., "channel for water;" late 14c., "flood-gate;" from water (n.1) + gate (n.). The name of a building in Washington, D.C., that housed the headquarters of the Democratic Party in the 1972 presidential election, it was burglarized June 17, 1972, which led to the resignation of President Nixon.
watering (n.): Old English wæterunge "a carrying water," verbal noun from water (v.). From late 14c. as "a soaking with water;" mid-15c. as "a giving water to (an animal);" c. 1600 as "salivation." Watering-can is from 1690s (earlier water-can, late 14c.); watering-hole is from 1882 (earlier water-hole, 1670s, watering-place, mid-15c.); by 1965 in the figurative sense "place where people meet and socialize over drinks."
waterline (n.): also water-line, 1620s, line where the water rises to on the hull of a ship afloat, from water (n.1) + line (n.).
waterlogged (adj.): 1759 (in an account of the Battle of Lagos in "Universal Magazine," September), from water (n.1) + log (n.); the notion apparently is of "reduce to a log-like condition."
WATER LOGGED, the state of a ship when, by receiving a great quantity of water into her hold, by leaking, &c., she has become heavy and inactive upon the sea, so as to yield without resistance to the efforts of every wave rushing over her decks. As, in this dangerous situation, the center of gravity is no longer fixed, but fluctuating from place to place, the stability of the ship is utterly lost. She is therefore almost totally deprived of the use of her sails, which would operate to overset her, or press the head under water. Hence there is no resource for the crew, except to free her by the pumps, or to abandon her by the boats as soon as possible. [William Falconer, "An Universal Dictionary of the Marine," London, 1784]
The verb waterlog (1779) appears to be a back-formation.
Waterloo (n.): village near Brussels; the great battle there took place June 18, 1815; extended sense of "a final, crushing defeat" is first attested 1816 in letter of Lord Byron. The second element in the place name is from Flemish loo "sacred wood" (see lea (n.)).
watermark (n.): also water-mark, 1708, "distinctive mark on paper," from water (n.1) + mark (n.1). Similar formation in German wassermarke. Not produced by water, but probably so called because it looks like a wet spot. The verb is recorded from 1866. Related: Watermarked.
watermelon (n.): 1610s, from water (n.1) + melon. So called for being full of thin juice. Compare French melon d'eau.
waterproof (adj.): also water-proof, 1725, from water (n.1) + proof (n.). Noun meaning "garment of waterproof material" is from 1799. The verb is first recorded 1843. Related: Waterproofed; waterproofing.
watershed (n.): "line separating waters flowing into different rivers," 1803, from water (n.1) + shed in a topographical sense of "ridge of high ground between two valleys or lower ground, a divide," perhaps from shed (v.) in its extended noun sense of "the part of the hair of the head" (14c.). Perhaps a loan-translation of German Wasser-scheide. Figurative sense is attested from 1878. Meaning "ground of a river system" is from 1878.
waterspout (n.): late 14c., "drainpipe," from water (n.1) + spout (n.). Meaning "whirlwind on open water" is recorded from 1738.
watertight (adj.): also water-tight, late 14c., from water (n.1) + tight (adj.). Figurative use from 1640s.
waterway (n.): Old English wæterweg; see water (n.1) + way (n.).
waterworks (n.): mid-15c., from water (n.1) + work (n.).