psilanthropism n.

before vowels psil-, word-forming element meaning "stripped, bare," used mostly in forming scientific terms, from Greek psilos "bare, naked; mere," perhaps akin to psēn "to rub," and both or either perhaps from PIE root *bhes- "to rub" (source also of Greek psamathos "sand;" see sand (n.)). Middle English had psilotre "a depilatory ointment" (c. 1400).

before a vowel, anthrop-, word-forming element meaning "pertaining to man or human beings," from Greek anthrōpos "man; human being" (including women), as opposed to the gods, from andra (genitive andros), Attic form of Greek anēr "man" (as opposed to a woman, a god, or a boy), from PIE root *ner- (2) "man," also "vigorous, vital, strong."

Anthropos sometimes is explained as a compound of anēr and ōps (genitive ōpos) "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." But Beekes writes, "As no IE explanation has been found, the word is probably of substrate origin."