de·con·di·tion 
(dē′kən-dĭshən)
(dē′kən-dĭshən)v. de·con·di·tioned, de·con·di·tion·ing, de·con·di·tions
v.tr.
1. Psychology To cause (a conditioned response) to become extinct.
2. To cause to decline from a condition of physical fitness, as through a prolonged period of inactivity or, in astronauts, through weightlessness in space.
v.intr.
To lose physical fitness.