flex

verb \ ˈfleks \

Definition of flex

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

See flex defined for English-language learners

See flex defined for kids

Examples of flex in a Sentence

He flexed the muscles of his right arm.
a material that flexes easily

Origin and Etymology of flex

borrowed from Latin flexus, past participle of flectere "to cause to go in a different direction, bend, curve," of uncertain origin

NEW! Time Traveler

First Known Use: circa 1521

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flex

noun

Definition of flex

chiefly British

: an electric cord

Origin and Etymology of flex

short for flexible cord

NEW! Time Traveler

First Known Use: 1905

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flex

noun

Definition of flex

: an act or instance of flexing

Origin and Etymology of flex

derivative of ¹flex

NEW! Time Traveler

First Known Use: circa 1934

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FLEX Defined for English Language Learners

flex

verb

Definition of flex for English Language Learners

: to bend (a body part)
: to move or tighten (a muscle)

FLEX Defined for Kids

flex

verb \ ˈfleks \

Definition of flex for Students

flexed; flexing

1 : to bend especially again and again

Can you flex your fingers?

2 : to move or tense (a muscle)

Word Root of flex

The Latin word flectere, meaning “to bend” or “to curve,” and its form flexus give us the roots flect and flex. Words from the Latin flectere have something to do with bending or curving. To flex is to cause something, such as a muscle, to curve or bend. Something flexible can be bent without breaking. To deflect, or turn aside, is to bend the direction of something. To reflect is to bend an image back to the person looking at a mirror or other shiny surface.