Anything that impels; a stimulating factor. / A force, either internal or external, that impels; an impulse. / The force or energy associated with a moving body; a stimulus.

Making arbitrary decisions, especially in an impulsive and forceful manner. / Characterized by sudden violence or vehemence.

(uncountable) The state or quality of being impetuous; making arbitrary decisions. / Result of being impetuous; arbitrary decisions.

In an impetuous manner; with sudden force

plural of impetus