jerkwater adj.

"to pull with sudden energy," 1580s; earlier "to lash, strike as with a whip" (1540s, surviving only in dialect), of uncertain origin, perhaps echoic. Intransitive sense of "make a sudden spasmodic motion" is from c. 1600. Compare Middle English yerkid, an adjective apparently meaning "pulled tight" (early 15c.), which has the form of a past participle. Also compare Middle English ferken "move hastily; drive (something) forward," from Old English fercian "to proceed." Related: Jerked; jerking.

Old English wæter, from Proto-Germanic *watr- (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, suffixed form of root *wed- (1) "water; wet."

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.).

"tedious and ineffectual person," 1935, American English carnival slang, of uncertain origin. Perhaps from jerkwater "petty, inferior, insignificant" [Barnhart, OED]; alternatively from, or influenced by, verbal phrase jerk off "masturbate" [Rawson]. The lyric in "Big Rock Candy Mountain," sometimes offered as evidence of earlier use, apparently is "Where they hung the Turk [not jerk] that invented work."

A soda-jerk (1915; soda-jerker is from 1883) is so called for the pulling motion required to work the taps.

The SODA-FOUNTAIN CLERK

Consider now the meek and humble soda-fountain clerk,

Who draweth off the moistened air with nimble turn and jerk,

[etc., Bulletin of Pharmacy, August, 1902]