before a vowel, anthrop-, word-forming element meaning "pertaining to man or human beings," from comb. form of Greek anthropos "man, human being" (sometimes also including women) from Attic andra (genitive andros), from Greek aner "man" (as opposed to a woman, a god, or a boy), from PIE *hner "man" (cf. Sanskrit nar-, Armenian ayr, Welsh ner).
Anthropos sometimes is explained as a compound of aner and ops (genitive opos) "eye, face;" so literally "he who has the face of a man." The change of -d- to -th- is difficult to explain; perhaps it is from some lost dialectal variant, or the mistaken belief that there was an aspiration sign over the vowel in the second element (as though *-dhropo-), which mistake might have come about by influence of common verbs such as horao "to see."