(uncountable) Flexibility, pliancy.

(countable) An act of flexing.

(uncountable, chiefly Britain) Any flexible insulated electrical wiring.

(uncountable) Flexible ductwork, typically flexible plastic over a metal wire coil to shape a tube.

(countable, geometry) A point of inflection.

(countable, slang) The act of flaunting something; something one considers impressive.

(transitive, chiefly physics or biomechanics) To bend something.

(transitive) To repeatedly bend one of one's joints.

(transitive) To move part of the body using one's muscles.

(intransitive) To tighten the muscles for display of size or strength.

(intransitive, slang, by extension) To flaunt one's superiority.