An outburst of rage, frustration, or ill temper. My mom's going to have a hissy when she sees what happened to the car! I was so embarrassed when Danny started having a hissy in the grocery store.
See also: hissy
Rur. a tantrum. (Often with throw. Probably refers to an angry, hissing cat.) Jane practically has a hissy fit every time she gets a run in her nylons. The boss is really mad today. It's just one hissy fit after another.