flex in WordNet English dictionary

1. cause (a plastic object) to assume a crooked or angular form
   "bend the rod"; "twist the dough into a braid"; "the strong man could turn an iron bar"
   flex  bend  deform  twist  turn 
   
2. bend a joint
   "flex your wrists"; "bend your knees"
   flex  bend 
   
3. form a curve
   "The stick does not bend"
   bend  flex 
   
4. contract
   "flex a muscle"
   flex 
   
5. exhibit the strength of
   "The victorious army flexes its invincibility"
   flex 
   

1. the act of flexing
   "he gave his biceps a flex to impress the ladies"
   flex