verb.
To move part of the body using one's muscles.
verb.
To tighten the muscles for display of size or strength.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
verb.
contract
verb.
cause (a plastic object) to assume a crooked or angular form
verb.
form a curve
noun.
the act of flexing
verb.
bend a joint
verb.
exhibit the strength of
Word Usage
"CLANCY: And it's a whole industry, because you've to have your cars -- in Brazil, you find most of the cars are what they call flex vehicles, so they can either run on ethanol, or they can run on regular unleaded gas."