Antonyms for powerless

all:

powerful.

weak; unable:

capable, competent, active, strong, lively, effective, able, powerful, potent, dominant.

noun:

dictatorial, capable, energetic, omnipotent, despotic, competent, effective, dynamic, efficient, all-powerful, regent, magisterial, able, important, senior, dominant, major, regnant, ruling, tough, puissant, sturdy, forceful, reigning, significant, tyrannical, coercive, vigorous, high-level, authoritarian, mighty, top, muscular, autocratic, compelling.