WordWeb Online

1. Get very angry and fly into a rage
   "The professor had a fit when the student didn't know the answer to a very elementary question";
   - flip one's lid [N. Amer, informal], blow up [informal], throw a fit [informal], hit the roof [informal], hit the ceiling [informal], blow one's stack [N. Amer, informal], fly off the handle [informal], flip one's wig [US, informal], lose one's temper, blow a fuse [informal], go ballistic [informal], go mental [informal], blow a gasket [informal], blow one's top [informal], go off the deep end [informal], go ape [informal]
    
2. Be very nervous, agitated or upset as a reaction to something
   - have a cow [N. Amer, informal], have kittens [Brit, informal], do one's nut [Brit, informal]

Derived forms: had a fit, having a fit, has a fit

Type of: rage