Synonyms to at the reins

in charge, ascendant, at the head, at the helm, boss, chief, commanding, controlling, dominant, general, governing, head, hegemonic, hegemonistic, in ascendancy, in authority, in chief, in command, in control, in custody, in detention, in hold, in power, in the ascendant, in the saddle, leading, master, on the throne, overseeing, paramount, predominant, predominate, prepollent, preponderant, preponderate, prepotent, prevalent, regnant, regulating, regulative, regulatory, reigning, ruling, sovereign, superintendent, supervising, supervisory, supreme, under close arrest, under house arrest, armipotent, authoritative, cogent, dynamic, effective, energetic, forceful, forcible, high-potency, high-powered, high-pressure, high-tension, in force, irresistible, mighty, mighty in battle, operative, potent, powerful, puissant, striking, strong, telling, valid, vigorous, vital