mid-14c., from Old French hiene, from Latin hyaena, from Greek hyaina "hyena," apparently a fem. formation from hys "pig," from PIE *su- "swine" (see sow (n.)). With fem. suffix -aina. So called for its bristles. Applied to cruel, treacherous, and greedy persons at least since 1670s. Adjectival forms that have been attempted in English include hyenaish, hyenaesque, hyenic, hyenine, hyenoid.
<a href="https://www.etymonline.com/word/hyaena">Etymology of hyaena by etymonline</a>
Harper, D. (n.d.). Etymology of hyaena. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/hyaena