1550s (adv.), 1630s (n.), from L. phrase ex tempore "offhand, in accordance with (the needs of) the moment," lit. "out of time," from ex- "out of" + tempore, abl. of tempus (gen. temporis) "time." Of speaking, strictly "without preparation, without time to prepare," but now often with a sense merely of "without notes or a teleprompter." Related: Extemporize (1717) "to speak ex tempore;" extemporizing.