vain
adjective uk/veɪn/ us/veɪn/
(NOT SUCCESSFUL)
C2 徒劳的；枉然的；无用的
unsuccessful; of no value
The doctors gave him more powerful drugs in the vain hope that he might recover. 医生们给他服用了更强效的药，希望他能够康复，却是徒然。
formal It was vain to pretend to himself that he was not disappointed. 他没办法欺骗自己说不觉得失望。
in vainC1 徒劳地；枉然地；无用地
unsuccessfully
I tried in vain to start a conversation. 我极力想挑起话头，但没有成功。
All the police's efforts to find him were in vain. 警方竭力想要找到他，但所有努力终是徒劳。
(SELFISH)
C2 虚荣的;自负的
too interested in your own appearance or achievements
He was very vain about his hair and his clothes. 他很虚荣，在发型和衣着方面非常讲究。