THESAURUS
flex
S-curve, arch, bend, bend back, bending, bow, bowing, cable, conflexure, contract, cord, crook, curl, curve, decurve, deflect, deflection, dome, embow, exercise, extension, flection, flexure, geanticline, geosyncline, give, hairpin turn, hook, hump, hunch, incurvate, incurve, inflect, inflection, lead, loop, meander, oxbow, recurve, reflect, reflection, reflex, retroflex, round, sag, stretch, swag, sweep, tense, tighten, turn, turning, vault, wind, wire
ROGET THESAURUS
flex
Curvature
VB
be curved curve, sweep, sway, swag, sag, deviate, curl, turn, reenter, render curved,
flex, bend, curve, incurvate, inflect, deflect, scatter, refract (light), crook, turn, round, arch, arcuate, arch over, concamerate, bow, curl, recurve, frizzle, rotundity, convexity.
Elasticity
VB
stretch,
flex, extend, distend, be elastic, bounce, spring back.