Definition of mess with someone's head in English:
US informal Cause someone to feel frustrated, anxious, or upset.
- I think there is a real live monkey living in my computer and he messes with my head by dealing me hands that cannot be won.
- You know, anybody who's gone without sleep, even for just one night, knows that it can really sort of, you know, mess with your head.
- He had offseason ankle surgery, and though trainer Dave England says the ankle no longer is bothering Johnson, it may be messing with his head.
Definition of mess with someone's head in:
- British & World English dictionary