flex your muscles
flex (one's) muscle(s)
1. Literally, to contract one's muscles, especially to demonstrate their size and subsequent strength. He's so vain, flexing his muscles in the mirror whenever he thinks no one is looking. She flexed her muscles and told us not to mess with her brother again.
2. By extension, to demonstrate one's influence, power, or strength. The small but outspoken nation has been flexing its muscles lately, with a wide range of military and ballistics demonstrations. The wealthy business tycoon flexed his muscle to get the charges dropped against his son.
See also: flex
flex your muscles
orflex your muscle
COMMON If people or organizations flex their muscles or flex their muscle, they behave in a way that is intended to show that they have power and are considering using it. A pro-democracy movement is starting to flex its muscles. The miners' actions last year seem to have encouraged workers in the oil industry to flex their industrial muscle.
flex your muscles
give a show of strength or power. 1998 Times Mr Prescott is flexing his muscles and the City is wondering just how far he is prepared to go.
flex your ˈmuscles
show that you are ready and prepared to use your power, abilities, etc: He’s flexing his muscles, waiting for the day he becomes president.Athletes flex (= stretch and tighten) their muscles before a race, a fight, a game, etc.