also: こまぬく
godan verb (-ku), transitive verb
Literally crossing one's arms over the chest. Often used in the set phrase 手をこまねく.
彼は黙って手をこまねいていた。
He silently folded his arms.
godan verb (-ku), transitive verb
Idiomatic use in phrases like 手をこまねく or 腕をこまねく, meaning to watch without taking action when one should intervene.
困っている人を見ても、手をこまねいているだけだった。
Even when seeing someone in trouble, he just stood by with his arms folded.