Whoop
Middle English: probably imitative.
wiktionary
From Middle English whopen, whowpen, howpen, houpen(“to whoop, cry out”), partially from Old French houper, hopper, houpper(“to shout”), from Proto-Germanic *hwōpaną(“to boast, threaten”) (compare Gothic 𐍈𐍉𐍀𐌰𐌽( ƕōpan, “to boast”), Old English hwōpan(“to threaten”)); and partially from Middle English wop(“weeping, lamentation”), from Old English wōp(“cry, outcry, shrieking, weeping, lamentation”), from Proto-Germanic *wōpaz(“shout, cry, wail”) (compare Old Norse ópa(“to cry, scream, shout”), Gothic 𐍅𐍉𐍀𐌾𐌰𐌽( wōpjan, “to cry out”)).
Corruption of whip.
etymonline
whoop (v.)
mid-14c., houpen, partly imitative, partly from Old French huper, houper "to cry out, shout," also imitative. It is attested as an interjection from at least mid-15c. Spelling with wh- is from mid-15c. The noun is recorded from c. 1600. Phrase whoop it up "create a disturbance" is recorded from 1881. Expression whoop-de-do is recorded from 1929. Whooping cough (1739) is now the prevalent spelling of hooping cough; whooping crane is recorded from 1791.
