"bend forward," Old English stupian "to bow, bend," from Proto-Germanic *stup- (source also of Middle Dutch stupen "to bow, bend," Norwegian stupa "fall, drop"), from PIE *(s)teu- (1) "to push, stick, knock, beat" (see steep (adj.)). Figurative sense of "condescend," especially expressing a lowering of the moral self, is from 1570s. Sense of "swoop" is first recorded 1570s in falconry. Related: Stooped; stooping. The noun meaning "an act of stooping" is from c. 1300. Stoop-shouldered attested from 1773.