Being in physical motion: active fish in the aquarium. Functioning or capable of functioning. Marked by energetic activity; busy: active stock and bond markets; spent an active day sightseeing. Involving or requiring physical exertion and energy: an active workout at the gym. Being in a state of action; not quiescent: active hostilities along the border. Erupting or liable to erupt; not dormant: an active volcano. Marked by or involving direct participation: took an active interest in politics; played an active role on the committee. Currently in use or effect: an active membership. Openly acknowledged or expressed: an active dislike of the new neighbors. Producing an intended action or effect: active ingredients. Grammar Indicating that the subject of the sentence is performing or causing the action expressed by the verb. Used of a verb form or voice. Grammar Expressing action rather than a state of being. Used of verbs such as run, speak, and move. Producing profit, interest, or dividends: active accounts; active stocks. Electronics Being a source of electrical energy, as a generator. Electronics Capable of converting or amplifying voltages or currents, as a diode or transistor. Being on full military duty and receiving full pay. Grammar The active voice. Grammar A construction or form in the active voice. A participating member of an organization: union actives.