inf. to overreact disproprionate to the situation at hand.
1a. "When my sister found me screwing her friend Becky on her bed, she had a cow."

1b. "Is she kissing him dude? I'm about to bash his &*%ing face in!"
"Don't have a cow man. Let the slore ride."
by redgyul September 24, 2004
an alteration of the term ' to have kittens' to strongly overreact to a situation.
I scratched my Dad's car and he had a cow -now I am not allowed to borrow it for a year!
by Intensity January 10, 2005
A frequent utterance of Bart Simpson, "Don't have a cow" dismisses the other person's feelings as overreactive to the situation. The person who expresses anger, shock, disgust, or any of several other negative feelings towards an action or person is seen as having a cow. The person who induces bovine delivery, either through doing it or telling of the activity, often tries to minimize the activity as something not so bad. Saying don't have a cow minimizes both the activity itself *and* the person's feelings who is having the cow.
Jimmy Joe had a cow when he learned that his best friend, John Jay, had bought a term paper online and passed it off as his own writing.

Billy Ray laughed at Jimmy Joe's shock that he could do such a thing. He sneered, "Don't have a cow, man! Professors never read those papers anyway."
by MsLi January 29, 2006
As in when a person will be extremely upset, angry, or suprised about something
Bob: Hey, did you hear about how Fred's house got bulldozed over while he was on vacation?

Joe: Yeah, he's going to have a cow when he finds out!
by AlmostNinja October 26, 2010
being extreamly stressed and pissed off
'chill man, don't have a cow'
by gib March 19, 2004
To completely and utterly flip the fuck out.
Mary really had a cow when she came home from work early caught me sticking it to her twin sister indabutt over the kitchen counter. Typical woman, always overreacting.
(have a cow)
by Nick D October 21, 2005
To have a cow means to have a melt down in a drastically unnecessary way.
Friend #1: "i KeEp StUbBiNg My Toe On ThIs WaLl"
Friend #2: "oh god she's gonna have a cow"
by mm.spook👻 January 14, 2021