motive

synonyms motive , impulse , incentive , inducement , spur , goad mean a stimulus to action. motive implies an emotion or desire operating on the will and causing it to act <a motive for the crime>. impulse suggests a driving power arising from personal temperament or constitution <buying on impulse>. incentive applies to an external influence (as an expected reward) inciting to action <a bonus was offered as an incentive>. inducement suggests a motive prompted by the deliberate enticements or allurements of another <offered a watch as an inducement to subscribe>. spur applies to a motive that stimulates the faculties or increases energy or ardor <fear was a spur to action>. goad suggests a motive that keeps one going against one's will or desire <thought insecurity a goad to worker efficiency>.