1. 振作…的精神;使受到鼓舞
If you buck someone up or buck up their spirits, you say or do something to make them more cheerful.
e.g. Anything anybody said to him to try and buck him up wouldn't sink in...
任何人对他说的任何劝他振作起来的话都不会起作用。
e.g. The aim, it seemed, was to buck up their spirits in the face of the recession.
其目的好像是为了给面临经济衰退的他们鼓劲儿打气。
2. 振作;积极行动起来
If you tell someone to buck up or to buck up their ideas, you are telling them to start behaving in a more positive and efficient manner.
e.g. People are saying if we don't buck up we'll be in trouble...
人们说,如果我们再不积极行动起来,我们就会有麻烦。
e.g. Buck up your ideas or you'll get more of the same treatment.
打起精神来,否则你会吃更多苦头。