1610s, of physical things, from French flexibilité (in Old French, "weakness, vacillation") or directly from Late Latin flexibilitatem (nominative flexibilitas), from Latin flexibilis "pliant, yielding" (see flexible). Of immaterial things from 1783.
he enjoyed the flexibility of his working arrangement
fleur-de-lis
fleuret
fleuron
flew
flex
flexibility
flexible
flexion
flexography
flexor
flextime