C2 unsuccessful; of no value徒勞的;枉然的;無用的
The doctors gave him more powerful drugs in the vain hope that he might recover.醫生們給他服用了更強效的藥,希望他能夠康複,卻是徒然。
formal It was vain to pretend to himself that he was not disappointed.他沒辦法欺騙自己說不覺得失望。
in vainC1 unsuccessfully徒勞地;枉然地;無用地
I tried in vain to start a conversation.我極力想挑起話頭,但沒有成功。
All the police's efforts to find him were in vain.警方竭力想要找到他,但所有努力終是徒勞。