source: By Paul Lacroix - http://www.gutenberg.org/files/10940/10940-h/10940-h.htm, Public Domain

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.

e.g. a motive for the crime

IMPULSE suggests a driving power arising from personal temperament or constitution.

e.g. buying on impulse

INCENTIVE applies to an external influence (such as an expected reward) inciting to action.

e.g. a bonus was offered as an incentive

INDUCEMENT suggests a motive prompted by the deliberate enticements or allurements of another.

e.g. offered a watch as an inducement to subscribe

SPUR applies to a motive that stimulates the faculties or increases energy or ardor.

e.g. fear was a spur to action

GOAD suggests a motive that keeps one going against one's will or desire.

e.g. thought insecurity a goad to worker efficiency

verb with object

1. provoke or annoy (someone) so as to stimulate some action or reaction:

〈人〉をけしかける, 駆り立てる(on); 〈人〉を駆り立てて «…» させる «into doing»

e.g. he goaded her on to more daring revelations.

2. drive or urge (an animal) on with a goad:

〈家畜など〉を突き棒で突く［追い立てる］

e.g. the cowboys goaded their cattle across the meadows.

a spiked stick used for driving cattle.

(家畜を追うための)突き棒

a thing that stimulates someone into action:

〈人〉をけしかける, 駆り立てる(on); 〈人〉を駆り立てて «…» させる «into doing»

e.g. for him the visit was a goad to renewed effort.

Old English gād, of Germanic origin.