Main Entry: ¹flex

Pronunciation: \ˈfleks\

Function: verb

Etymology: Latin flexus, past participle of flectere to bend

Date: circa 1521

transitive verb 1 : to bend especially repeatedly
2 a : to move muscles so as to cause flexion of (a joint) b : to move or tense (a muscle) by contraction
3 : use, demonstrate <flexing her skills as a singer>intransitive verb : bend

— flex one's muscles : to demonstrate one's strength <an exaggerated need to flex his political muscles — J. P. Lash>