To bend; as, to flex the arm.
- To bend (something pliant or elastic).
- To bend (a joint).
- To bend (a joint) repeatedly.
- To contract (a muscle, for example).
- To move by muscular control: "Sandy flexes his brow characteristically” ( Scott Turow).
- To exhibit or show off the strength of: "They had spent six years since the lightning Six Day War flexing their invincibility” ( Howard Kaplan).
- To bend: "His hands flexed nervously as he spoke” ( Mary McCarthy).
- Chiefly British Flexible insulated electric cord.
- The act or an instance of flexing; a bending.
- Pliancy; flexibility: "'Resolution' has none of that modern flex we favor, with generous, built-in amounts of 'maybe'” ( Melvin Maddocks).
- flex (one's) muscles Informal To exhibit or show off one's strength.