skate (n.1) Look up skate at Dictionary.com
"type of flat, cartilaginous fish, a kind of ray," mid-14c., from a Scandinavian source such as Old Norse skata "skate," Danish skade, Faeroese skøta, of unknown origin.
skate (n.2) Look up skate at Dictionary.com
"ice skate," 1660s, skeates "ice skates," from Dutch schaats (plural schaatsen), a singular mistaken in English for plural, from Middle Dutch schaetse. The word and the custom were brought to England after the Restoration by exiled followers of Charles II who had taken refuge in Holland.

The Dutch word is from Old North French escache "a stilt, trestle," related to Old French eschace "stilt" (French échasse), from Frankish *skakkja "stilt" or a similar Germanic source (compare Frisian skatja "stilt"), perhaps literally "thing that shakes or moves fast" and related to root of Old English sceacan "to vibrate" (see shake (v.)). Or perhaps [Klein] the Dutch word is connected to Middle Low German schenke, Old English scanca "leg" (see shank). Sense alteration in Dutch from "stilt" to "skate" is not clearly traced. Sense in English extended to roller-skates by 1876. Meaning "an act of skating" is from 1853.
skate (v.) Look up skate at Dictionary.com
1690s, "to ice-skate," from skate (n.2). U.S. slang sense of "to get away with something" is attested from 1945. Related: Skated; skating.