flex one's muscles

flex (one's) muscle(s)

1. Literally, to contract one's muscles, especially to demonstrate their size and 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 demonstrations. The wealthy business tycoon flexed his muscle to get the charges dropped against his son.
See also: flex

flex one's muscles

Show off one's strength or power, as in The boys love flexing their muscles, or The new department head has decided to flex her muscles. [Early 1900s]
See also: flex, muscle
References in periodicals archive ?
More than the experience, what I am grateful for is the building of 'spiritual muscle.' This happens in an environment where one is able to experience the blessings of the Divine and one learns to flex one's muscles of discernment because of the clarity that exists in a non-chaotic environment.
Mergers and acquisitions, competition and the economy are making "partnerships," a sometimes necessary, but also very fashionable way to flex one's muscles in the marketplace.