Middle English enfeblen, from Anglo-French enfebler, enfeblir, from en- + feble feeble
verb
to make feeble : deprive of strength
weakenenfeebledebilitateunderminesapdisable mean to lose or cause to lose strength or vigor. weaken may imply loss of physical strength, health, soundness, or stability or of quality, intensity, or effective power. enfeeble implies a condition of marked weakness and helplessness.