PUT UP OR SHUT UP

v. phr. informal 1. To bet your money on what you say or stop saying it. Often used as a command; often considered rude. The man from out of town kept saying their team would beat ours and finally John told him "Put up or shut up." 2. To prove something or stop saying it. Often used as a command; often considered rude. George told Al that he could run faster than the school champion and Al told George to put up or shut up.