flex-v; 3 Senses

Sense Number 1: contract, as a muscle

Commentary: Syntax includes: NP1[agent[animate|organization]] FLEX NP2[patient[body_part]] (PP[cause]) (PP[recipient]) NP1[patient[body_part]] FLEX (PP[cause]) (PP[recipient])

You could see his hands flexing, already pulling the trigger.
She caught a glimpse of Stresa's quilled body flexing.
Iran flexes its military muscles.
Ivory Latta flexed her muscles at LeBron James.
He flexed his muscles at the thought of finally choosing.

VerbNet: crane-40.3.2
FrameNet: Body_movement
PropBank: flex.01
WordNet 3.0 Sense Numbers: 1, 2, 4

Sense Number 2: cause something flexible to bend

Commentary: Syntax includes: NP1[agent|cause] FLEX NP1[patient] NP1[patient] FLEX (PP[cause])

The bridge flexed under Farinelli's weight.
The RV rippled and flexed.
The bristly tentacle around Conan's waist flexed.
I actually gently flexed the rod against the floor.
We flex the rod when we flycast.
The sling-holder's weight flexed the beam.

VerbNet: bend-45.2
FrameNet: NM
PropBank: flex.02
WordNet 3.0 Sense Numbers: 3

Sense Number 3: cause an object to assume a bent or crooked form

Commentary: Syntax includes: NP1[agent] FLEX NP2[material] PP[product]

He flexed the rod into a right angle.

VerbNet: bend-45.2,knead-26.5
FrameNet: NM
PropBank: flex.02