Ex-tĕm'po-rā'ne-oŭs, a.

a. [Lat. ex tempore, q. v.; Sp. extemporaneo, Fr. extemporané, It. estemporaneo.] Proceeding from the impulse of the moment; called forth by the occasion; composed, performed, or uttered, without previous study; unpremeditated; off-hand; extemporary; as, an extemporaneous address; an extemporaneous production; an extemporaneous prescription.