flex

flex — noun

1. a bendable wire covered in plastic or rubber that connects an electrical device

1.nounB1
Definition

a bendable wire covered in plastic or rubber that connects an electrical device to the mains power supply

Example

Tamar replaced the damaged flex on her desk lamp after it started sparking.

collocation: damaged flex

The vacuum cleaner's flex was too short to reach the far side of the room.

Common collocations
  • damaged flex
  • extension flex
  • replace a flex
  • coil a flex
Synonyms
  • cord

    common in American English; slightly more general

  • cable

    usually thicker and stronger than household flex

  • lead

    British term for a power cord, often interchangeable with flex

Usage Note

In British English, flex is the ordinary word for the cord that supplies electricity to an appliance. American English prefers cord or power cord.

2. the act of making a joint bend or a muscle become tight and firm

2.nounB1
Definition

the act of making a joint bend or a muscle become tight and firm

Example

The physiotherapist asked Hamza to hold the flex of his bicep for five seconds.

hold the flex of [body part]

Each flex of her calf muscle helped Soraya push harder on the bicycle pedal.

flex of [body part]

Common collocations
  • hold a flex
  • controlled flex
  • slow flex
  • painful flex
Synonyms
  • contraction

    focuses on the muscle shortening, not the joint bending

  • bend

    less specific; used for both joints and materials

Antonyms
  • extension

    the straightening of a joint, opposite of bending

3. the quality that lets a solid material be curved many times without getting dama

3.nounB2
Definition

the quality that lets a solid material be curved many times without getting damaged

Example

The engineers tested the flex of the new composite material under extreme heat.

test the flex of [material]

This type of rubber has excellent flex and returns to its original shape quickly.

excellent flex

Common collocations
  • test the flex
  • excellent flex
  • repeated flex
  • check the flex
Synonyms
  • flexibility

    more common and general term; flex is often used in technical contexts

  • pliability

    emphasises the ability to be shaped without springing back

Antonyms

4. a flat or room that has a light movable wall put in so it has an additional livi

4.nounC1
Definition

a flat or room that has a light movable wall put in so it has an additional living space

Example

The homeowners turned the one-bedroom flat into a flex by adding a lightweight dividing wall.

turn [room] into a flex

The landlord advertised the property as a two-bedroom flex with a removable partition.

Common collocations
  • create a flex
  • a two-bedroom flex
  • rent a flex
  • convert into a flex
Synonyms
  • partition

    a lightweight wall, not necessarily creating a separate room

Usage Note

This term is used mainly in British property advertisements and housing regulations. It is rare in everyday conversation or in American English.

5. something a person owns or has achieved that they proudly draw attention to, oft

5.nounB2
Definition

something a person owns or has achieved that they proudly draw attention to, often in a way that irritates other people

Example

Showing everyone his new watch was just another flex that annoyed his colleagues.

Sari's biggest flex is that she ran a marathon without any training beforehand.

biggest flex

Common collocations
  • biggest flex
  • main flex
  • unnecessary flex
  • another flex
Synonyms
  • status symbol

    an object that shows wealth or high social position, not necessarily annoying

Usage Note

This sense is informal and frequently used in social media and casual conversation. It often carries a slightly negative or mocking tone.

Common Mistakes

His new car is a biggest flex.
His new car is the biggest flex.
use the with a superlative adjective before flex.

flex — verb

Word family

Synonym discussion

Sense: verb/1

All four words relate to making a body part or muscle change shape or tension, but they differ in focus. Bend is the most general — you can bend your knees, elbows, or back, and it describes the joint's angle rather than the muscle state. Tense is narrower: it describes the conscious act of making a muscle hard without necessarily changing a joint's position (e.g. tense your stomach muscles while sitting still). Contract is the technical term for what muscles do internally; a doctor might say "the heart contracts 70 times a minute." Tighten overlaps with tense but is more everyday — you tighten your grip on a rope or tighten your stomach before a punch. Flex (verb/1) combines both the joint movement and the muscle hardening, and is the preferred word in fitness and sports contexts. For example, "Christopher flexed his arm and watched his bicep rise" suggests both the bending of the elbow and the bulging of the muscle — something bend alone would not capture.

bend ↗tense ↗contract ↗tighten ↗

Common collocations

Nouns

Adverbs

Phrases

Prepositions

Etymology

LatinFrenchEnglish

Flex comes from the Latin verb flectere, meaning 'to bend.' It entered English through Old French fléchir in the 1500s, originally referring only to bending the body or objects. The physical sense of contracting muscles appeared in the 1800s. By the 1990s, African American Vernacular English developed the slang use meaning 'to show off or boast,' based on the idea of flexing muscles as a display of strength.