“闲着”的英语可以翻译为：at a loose end，be at grass ...

他用闲着的那只手摸我的夹克。He pawed at my jacket with his free hand.别的孩子都忙着,你不要闲着袖手旁观.Don't just sit by while the other children are all busy.他失业后一直在这里闲着.Since he lost his job, he's been hanging around here....