Godan verb with 'u' ending, Intransitive verb
to strike back at; to bite back; to turn on; to rise against; to oppose; to defy
ウサギでさえ、いじめられて片隅に追いつめられると、刃向かってくるだろう。Even a rabbit, if badgered into a corner, will fight back.
Also written 歯向う【はむかう】、刃向かう【はむかう】