from The American Heritage® Dictionary of the English Language, 4th Edition
- transitive v. Psychology To cause (a conditioned response, such as a phobia) to become extinct.
- transitive v. To cause to decline from a condition of physical fitness, as through a prolonged period of inactivity or, in astronauts, through weightlessness in space.
- intransitive v. To lose physical fitness.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- v. To adapt to a less demanding environment than that to which one was previously conditioned.
de- + condition (Wiktionary)