godan verb (-ru)
chicken out; get scared and back down
Slang verb meaning to lose one's nerve and avoid doing something frightening or risky. Often used among younger speakers.
ジェットコースターに乗るって言ったのに、チキっちゃった。
I said I'd ride the roller coaster, but I chickened out.
彼
He was going to confess, but he got scared and backed down.