To hightail is to leave a place very fast because you want to get away. In real talk it is almost always hightail it: We’d better hightail it out of here. It is informal American English — fine with friends, in a story, or in a film, but not in a careful letter. It comes from high + tail: deer and other animals lift the tail when they run from danger, and the word keeps that picture. You hightail it when something has gone wrong, when you are late, or when you simply do not want to stay. You would not use it for a calm, planned goodbye. British speakers understand it, though actually they may be more likely to say dash off or get out of here.

趕緊開溜、迅速跑掉（口語，美式；常說 hightail it）