ex·pire / ikˈspīr/ • v. 1. [intr.] (of a document, authorization, or agreement) cease to be valid, typically after a fixed period of time: the old contract had expired. ∎ (of a period of time) come to an end: the three-year period has expired. ∎ (of a person) die.2. [tr.] exhale (air) from the lung.