/veɪn ||; ven/adj1 useless; failing to produce the result you want 无用的；徒劳的: She turned away in a vain attempt to hide her tears. 她转过身去，想要掩饰自己的眼泪，可惜白费力气。
2 (used about a person) too proud of your own appearance, abilities, etc （指人）爱虚荣的，自负的，自视过高的:
He's so vain -- he looks in every mirror he passes. 他很爱虚荣，每经过一面镜子都要照一照。 ☞noun vanity 名词为vanity ➔vainly adv in vain without success 徒然；白费力:
The firemen tried in vain to put out the fire. 消防员尝试扑灭那场火，可惜徒劳无功。