Origin of thwackprobably echoic
transitive verbthwacked, thwack·ing, thwacks
Origin of thwackImitative.
(third-person singular simple present thwacks, present participle thwacking, simple past and past participle thwacked)
From a variant (influenced by whack) of Middle English thakken (â€œto strokeâ€), from Old English Ã¾accian (â€œto touch gently, stroke, tapâ€), from Proto-Germanic *Ã¾akwÅnÄ… (â€œto touch lightlyâ€), from Proto-Indo-European *tag-, *taÇµ- (â€œto touchâ€). Cognate with Old Dutch Ã¾akolÅn (â€œto strokeâ€), Old Norse Ã¾ykkr (â€œa thwack, thump, blowâ€), Icelandic Ã¾jÃ¶kka, Ã¾jaka (â€œto thwack, thump, beatâ€), Norwegian tjÃ¥ka (â€œto strike, beatâ€), Latin tangÅ (â€œtouchâ€). More at tangent.