Call somebody’s bluff
Definition 1 of 1
Pro Tip 1/3Poker Origin
The phrase originates from the game of poker, where bluffing is a key strategy. 
He claimed he would move abroad, but I called his bluff and he admitted he wasn't serious.
Pro Tip 2/3Skepticism Required
Use this phrase when you're skeptical about someone's claims and want to challenge them. 
She said she could eat 50 hot dogs, so I called her bluff to see if she could really do it.
Pro Tip 3/3Not Always Serious
Sometimes 'call someone's bluff' is used humorously, rather than confronting a serious threat. 
Jake joked about shaving his head, so we called his bluff and handed him the clippers.