Origin of capsize18th-c. naut. slang; uncertain or unknown; perhaps altered (infl. by dialect, dialectal cap, to overtop + side) ; from Spanish cabezar, literally , to sink by the head (; from cabo, cabeza, head)
intr. & tr.v.cap·sized, cap·siz·ing, cap·siz·es
Origin of capsizePerhaps from Spanish capuzar, to load a ship so that its bow sinks (perhaps alteration of chapuzar, to duck, push underwater, from Vulgar Latin *subputeare : Latin sub-, sub- + puteus, well; see pit1), or from Spanish cabezar, to pitch (from cabeza, head, from Vulgar Latin *capitia, from Latin caput, capit-; see cape2).
(third-person singular simple present capsizes, present participle capsizing, simple past and past participle capsized)
Attested since 1788 CE. Origin unknown. Possibly related to Spanish chapuzar (“to sink by the head”).