bum out
1. Depress, sadden, dispirit, as in He's been really bummed out since his girlfriend moved to California. [Slang; late 1960s]
2. Annoy, irritate, vex, as in That haircut will really bum out his parents. [Slang; c. 1970]
3. Fail badly, as in I got through the midterm, but I bummed out totally on the final exam. This usage is student slang. [Late 1960s]