'have kittens' definitions:

Get very angry and fly into a rage; "The professor combusted when the student didn't know the answer to a very elementary question"; "Spam makes me go ballistic" [syn: flip one's lid, blow up, throw a fit, hit the roof, hit the ceiling, have kittens, have a fit, combust, blow one's stack, fly off the handle, flip one's wig, lose one's temper, blow a fuse, go ballistic]