water-ski (n.)

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.).

in early use often skee, "one of a pair of long, slender boards or slats fastened to the feet and used to glide over snow," 1883 (there is an isolated instance from 1755), from Norwegian ski, related to Old Norse skið "long snowshoe," literally "stick of wood, firewood," cognate with Old English scid "stick of wood," obsolete English shide "piece of wood split off from timber;" Old High German skit, German Scheit "log," from Proto-Germanic *skid- "to divide, split," from PIE root *skei- "to cut, split."

THE new sport which has lately been introduced at Beloit is skeeing. They are long ash planks, carefully planed and turned up at the end, and are warranted to take you down hill quicker than a wink. After some practice performers become very expert, and the speed with which they go is something surprising. [Beloit College, Wisconsin, Round Table, Dec. 18, 1885]

Ski-jumper is attested from 1894; ski bum, a skiing enthusiast who works casual jobs at resorts for the opportunity to ski, is attested by 1960; ski-mask, originally to protect the face while skiing, is from 1963; noted as part of criminal disguises by 1968.