recalcitrant (adj) – extremely stubborn and unwilling to obey; hard to deal with or manage
BREAKDOWN: RE- (back) + CALC- (heel) + -ANT (inclined to)
— recalcitrance is defiance, impudence, or unruliness (also recalcitrancy)
This word is built on the root CALC-, which means small stone, pebble used for counting, lime or calcium, or heel.
Common CALC- words include calcium, calculator, chalk, and miscalculate.
More esoteric CALC- words include calx, calcareous, and calculous.