Verbs

(v)supplemake pliant and flexible“These boots are not yet suppled by frequent use”

Adjectives

(s)lissome, lissom, lithe, lithesome, supple, sinuousgracefully thin and bending and moving with ease
(s)limber, supple(used of e.g. personality traits) readily adaptable“a supple mind”, “a limber imagination”
(s)limber, supple(used of persons' bodies) capable of moving or bending freely