1. A name formerly given to absence of feeling or emotion, as seen in depression or the dysthymic disorder: In Rebecca's journals, which were written 100 years ago, she referred to experiencing a state of athymia which sounded as if she were depressed.
2. Apathy, emotional indifference, or unresponsiveness: Because of Teresa's persisting athymia, Dr. Brown prescribed a mild antidepressant.

Priscilla's athymia was expressed by the fact that she didn't care if she got any better or not, nor whether she would live or die.

3. A congenital lack at birth of a thymus gland (an organ situated in the center of the upper chest just behind the breastbone that assists the immune system): Dr. Bowers noted that, given the athymia of her patient, a regimen of medications to counter the inherent immunodeficiency was necessary.