Translation guide
The English phrase 'fold one's arms' can refer to a physical action or a metaphorical stance. In Japanese, different expressions are used depending on the nuance.
Describing the physical posture of crossing one's arms in front of the chest.
The most common and neutral way to say 'fold one's arms'. It literally means 'to cross one's arms'.
彼は腕を組んで考え込んでいた。
He was deep in thought with his arms folded.
a person standing with their arms folded
A slightly more formal or literary variant. Often used in written descriptions.
彼は腕組みをして窓の外を見ていた。
He was looking out the window with his arms folded.
Expressing the idea of standing by and doing nothing, often out of stubbornness or protest.
Literally 'to fold one's arms', but used idiomatically to mean 'to look on without doing anything', 'to stand by idly'. Often used in negative contexts.
困っている人を見て、腕をこまねいているだけではいけない。
You can't just fold your arms and watch when someone is in trouble.
彼はいつも腕をこまねいて、自分からは何もしない。
He always folds his arms and never does anything on his own.
Similar to 腕をこまねく, but uses 'hands' instead of 'arms'. Also means to stand by idly.
手をこまねいて見ているだけでは問題は解決しない。
Just folding your hands and watching won't solve the problem.
Describing alternative ways of folding arms, such as behind the back or with a specific grip.
Specifically means to fold one's arms behind one's back.
彼は後ろ手を組んで歩いていた。
He was walking with his arms folded behind his back.
To fold one's arms tightly, often conveying stubbornness or defensiveness.
彼女は腕を固く組んで、話を聞こうとしなかった。
She folded her arms tightly and refused to listen.
Be careful not to use 腕を組む when you mean the idiomatic 'fold one's arms and do nothing'. Use 腕をこまねく for that meaning. Conversely, 腕をこまねく is not used for the simple physical action.