chicken out
phrasal verb with chicken verb uk/ˈtʃɪk.ɪn/ us/ˈtʃɪk.ɪn/
slang disapproving
（因害怕而）退缩，放弃
to decide not to do something because you are too frightened
I was going to go bungee jumping, but I chickened out. 我原打算去玩蹦极跳的，可是因为害怕放弃了。