killyoudaoicibaDictYouDict[kill 词源字典]
kill: [13] The Old English verbs for ‘kill’ were slēan, source of modern English slay, and cwellan, which has become modern English quell. The latter came from a prehistoric Germanic *kwaljan, which it has been suggested may have had a variant *kuljan that could have become Old English *cyllan. If such a verb did exist, it would be a plausible ancestor for modern English kill.

When this first appeared in early Middle English it was used for ‘hit’, but the meanings ‘hit’ and ‘kill’ often coexist in the same word (slay once meant ‘hit’ as well as ‘kill’, as is shown by the related sledgehammer); the sense ‘deprive of life’ emerged in the 14th century.
[kill etymology, kill origin, 英语词源]
kill (v.)youdaoicibaDictYouDict
c. 1200, "to strike, hit, beat, knock;" c. 1300, "to deprive of life," perhaps from an unrecorded variant of Old English cwellan "to kill" (see quell), but the earliest sense suggests otherwise. Sense in to kill time is from 1728. Related: Killed; killing. Kill-devil, colloquial for "rum," especially if new or of bad quality, is from 1630s.
kill (n.2)youdaoicibaDictYouDict
"stream," 1630s, American English, from Dutch kil, from Middle Dutch kille "riverbed," especially in place names (such as Schuylkill). A common Germanic word, the Old Norse form, kill, meant "bay, gulf" and gave its name to Kiel Fjord on the German Baltic coast and thence to Kiel, the port city founded there in 1240.
kill (n.1)youdaoicibaDictYouDict
early 13c., "a stroke, a blow," from kill (v.). Meaning "act of killing" is from 1814; that of "a killed animal" is from 1878. Lawn tennis serve sense is from 1903. The kill "the knockout" is boxing jargon, 1950.