In psychology, an internal force that leads persons to act against their will. A “compulsive” act cannot be controlled: “Smith was a compulsive gambler.”
compulsion com·pul·sion (kəm-pŭl'shən)
n.
An uncontrollable impulse to perform an act, often repetitively, as an unconscious mechanism to avoid unacceptable ideas and desires which, by themselves, arouse anxiety.