verb, adverb, pronoun, measure word · to exchange goods or services for money

他在街上卖苹果。

verb · to be disloyal to a person, country, or cause

你竟然为了这点小利就把朋友卖了。

verb · to exert oneself to the utmost

为了通过考试，他工作起来特别卖力气。

verb · to display one's abilities or appearance to attract attention or admiration

你别在那儿卖乖了，快去干正事。