flexing
v.v. bending or tightening a muscle to show how strong it is. In a casual way, it can also mean showing off your money, skills, or expensive things to impress others.
v. contracting a muscle to increase its volume or tension. In contemporary slang, it refers to the act of ostentatiously displaying one's wealth, status, or accomplishments to assert superiority.
He is flexing his muscles in front of the mirror.
She was flexing her new designer watch on social media to make her friends jealous.
The athlete spent several minutes flexing for the cameras after his victory, while his rivals were already flexing their political influence to secure better sponsorship deals for the next season.
Often used as a gerund or present participle; the slang sense is frequently used intransitively.