pliant (adj.)

late 14c., pliaunt, "capable of being easily bent, flexible, supple," from Old French ploiant "bending, supple; compliant, fickle," as a noun, "turncoat" (13c.), present participle of ploier "to bend," from Latin plicare "to fold, lay" (from PIE root *plek- "to plait"). Figurative sense of "readily influenced (for good or ill), easily persuaded" is from c. 1400. Related: Pliancy.