v.
1. intr. (of a period of time, validity, etc.) come to an end.
2 intr. (of a document, authorization, etc.) cease to be valid; become void.
3 intr. (of a person) die.
4 tr. (usu. foll. by from; also absol.) exhale (air etc.) from the lungs.
Derivatives:
expiratory adj. (in sense 4).
Etymology: ME f. OF expirer f. L exspirare (as EX-(1), spirare breathe)