Call someone’s bluff

(PW) have someone prove what he says

I don’t think Bob knows as much as he says. I think we should call his bluff.

(dictionary)

call someone's bluff, to expose a person's deception; challenge someone to carry out a threat: He always said he would quit, so we finally called his bluff.

(free)

all someone's bluff

to demand that someone prove a claim or is not being deceptive. All right, I'll call your bluff. Show me you can do it! Tom said, "You've made me really angry, and I'll punch you if you come any closer!" "Go ahead," said Bill, calling his bluff.

call somebody's bluff

to make someone prove that what they are saying is true, or to make someone prove that they will really do what they say they will do, because you do not believe them

Usage notes: If you are playing a card game and you call someone's bluff, you force them to show you the cards they have.

Alice called his bluff and dared him to tell everyone what he knew about her.

call your bluff

to make someone do what they said they will do He said he would help, and now his opponents have called his bluff and asked him to provide the funds.

(your)

call someone's bluff idiom

Expose someone's deception, invite a showdown, as in I don't believe they have enough capital; I'm going to call their bluff. This term comes from poker, where bluffing (pretending) that one has better cards than one's opponents is an intrinsic part of the game, and calling someone's bluff means forcing them to show their cards. By the late 1800s it was being applied to other enterprises. Also see show one's hand.

(about)

Definition: challenge someone to prove what they say is true; not believe what someone is saying

Explanation: Usually used to state that you do not believe what someone is saying or that you think they are exaggerating. Also used in poker

Examples: I called his bluff and he admitted he had made up the whole story. - I called his bluff - he only had an Ace and a pair of twos.

(phraseFinder)

The phrase "call your bluff" comes from poker, a card game.
: : Here's a definition of "bluff":
: : bluff1
: : v. bluffed, bluff·ing, bluffs
: : v. tr.
: : To mislead or deceive.
: : To impress, deter, or intimidate by a false display of confidence.
: : Games To try to mislead (opponents) in a card game by heavy betting on a poor hand or by little or no betting on a good one.
: : v. intr.
: : To engage in a false display of strength or confidence.
: : n.
: : The act or practice of bluffing.
: : One that bluffs.
: : [Probably from Dutch bluffen, from Low German.]
: : bluffa·ble adj.
: : bluffer n.
: : The American Heritage® Dictionary of the English Language, Fourth Edition. Copyright © 2000 by Houghton Mifflin Company. Published by the Houghton Mifflin Company. All rights reserved.

: : "Call" and "bluff" are specific terms in poker.
: Literally, in poker, to call a bluff means "To equal the bet of (the preceding bet or bettor) in a poker game" (American Heritage Dictionary).

: Thus to CALL someone's bluff means to say, in effect, I think you're just bluffing; let's see what you've got; put your money where your mouth is; put up or shut up; etc.