adj. Intoxicating or stupefying: heady liqueur. adj. Tending to upset the mind or the balance of senses: standing on a heady outcrop of rock. adj. Serving to exhilarate: the heady news of triumph. adj. Impetuous and rash: a heady outburst of anger. adj. Domineering; overbearing: too heady to reason with. adj. Swift and violent; headlong: a heady current. adj. Showing intelligence and good judgment; prudent: heady tactics. adj. Suffering from a headache: a heady, throbbing feeling.