Is it ensure, insure, or assure?
1540s, originally "to clear the throat, to cough up phlegm," from Old English hræcan "to cough up, spit" (related to hraca "phlegm"), from Proto-Germanic *khrækijanan (cf. Old High German rahhison "to clear one's throat"), of imitative origin (cf. Lithuanian kregeti "to grunt"). Meaning "to make efforts to vomit" is from 1850; sense of "to vomit" is first attested 1888. Related: Retched; retching.
v. retched, retch·ing, retch·es
To try to vomit.