Definition of have a cow in English:

have a cow

phrase

North American
informal
  • Become angry, excited, or agitated.

    ‘don't have a cow—it's no big deal’
    • ‘So, if you're having a cow about the prospect of dating someone you work with - well, you should be.’
    • ‘Her sister did the same thing and you didn't have a cow.’
    • ‘I'm in there for forty-five minutes and you start to have a cow!’
    • ‘Well, mom's having a cow so why don't you do the right thing and go to sleep.’
    • ‘You better get going or your mom's going to have a cow.’
    • ‘Sometimes I wish I could wring that man's neck for the games he plays while I'm on the other side of the world having a cow!’
    • ‘I'm afraid Mr. Napper is going to come across some of it and have a cow.’
    • ‘Aunt Beth is having a cow about the messes I always make.’
    • ‘I'm just relaying the message, don't have a cow.’
    • ‘People would, well, have a cow, and for good reason.’