Dictionary.com
definitions

athymia

[ə-thī′mē-ə]
n.
  1. The absence of emotion; morbid impassivity.
  2. The absence of the thymus gland or the suppression of its secretion.athymism
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.