/keuhm pul"sheuhn/ , n.
1. the act of compelling; constraint; coercion.
2. the state or condition of being compelled.
3. Psychol. a strong, usually irresistible impulse to perform an act, esp. one that is irrational or contrary to one's will.
[ 1375-1425; late ME ( compulsion- (s. of compulsio ), equiv. to L compuls ( us ), ptp. of compellere to COMPEL ( com- COM- + pul- var. s. + -sus ptp. suffix) + -ion- -ION ]