c. 1200, adjective developed from Old English holh (n.) "hollow place, hole," from Proto-Germanic *hul-, from PIE root *kel- (1) "to cover, conceal, save." The figurative sense of "insincere" is attested from 1520s. Related: Hollowly. Spelling development followed that of fallow, sallow. Adverbial use in carry it hollow "take it completely" is first recorded 1660s, of unknown origin or connection. Hollow-eyed "having deep, sunken eyes" is attested from 1520s.
"having large, full eyes," 1620s, from ox + -eyed. An epithet used by Homer (boōpis) of the goddess Hera (Juno) and beautiful women. Oxeye has since c. 1400 been a name given to various flowering plants thought to resemble the eye of an ox; it is also used of certain birds, fishes, and a type of mirror.