Wiktionary
vb. (label en slang) to become angry or upset about something
WordNet
v. go mad, go crazy; "He flipped when he heard that he was being laid off" [syn: flip]
Usage examples of "flip out".
It's hard enough being one of the six or seven sane people in America without having my best friend flip out totally.
He paused to flip out his phone and punch Max's speed dial number.
She dipped into her vest pocket, feinted at her opponent, and took advantage of his dodge to flip out one of the flat skipping-stone knives.
Besides, Jenks would flip out if I so much as hinted at a kitten, and Ivy had given her owls to her sister after one narrowly escaped being torn apart when it caught Jenks’.
Might he be sitting on all sorts of internal turmoils and ready to flip out anytime?
I thought she'd flip out, but it seems to have put her back on her feet.
Sunflower did a flip out of the chute, landing on her (and Joe's) back, and the crowd let out a shrill gasp because it looked as if Joe had been killed.