lose (one's) mind(redirected from lost mind)
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lose (one's) mind
1. To become insane or mentally unsound; to become extremely foolish or foolhardy. I'm going to lose my mind if I have to hear that song one more time! I think Jane's grandmother has lost her mind lately. You must have lost your mind if you think that's a good idea!
2. To become exasperated, typically due to attempting a difficult undertaking or dealing with a challenging situation. Often used in the continuous tense. I've been losing my mind trying to juggle work, night school, and the kids. Millie was losing her mind trying to prepare food and manage the front of the house, but thankfully she was able to hire someone to help.
lose one's mind
Also, lose one's reason. Go crazy, lose one's sanity, as in I thought she'd lost her mind when she said she was going ice-fishing, or That assignment is enough to make me lose my reason. The first expression dates from the late 1500s; the second employs reason in the sense of "unimpaired mental faculties," a usage dating from the late 1300s. Also see under go out of one's mind; have all one's buttons.