1. To breathe out; to emit from the lungs; to throw out from the mouth or nostrils in the process of respiration; opposed to inspire. Anatomy exhibits the lungs in a continual motion of inspiring and expiring air. (Harvey) This chafed the boar; his nostrils flames expire. (Dryden)
2. To give forth insensibly or gently, as a fluid or vapor; to emit in minute particles; to exhale; as, the earth expires a damp vapor; plants expire odors. The expiring of cold out of the inward parts of the earth in winter. (Bacon)
3. To emit; to give out.