A power affecting a person, thing, or course of events, especially one that operates without any direct or apparent effort: relaxed under the influence of the music; the influence of television on modern life. Power to sway or affect based on prestige, wealth, ability, or position: used her parent's influence to get the job. A person who exerts influence: My parents considered my friend to be a bad influence on me. An effect or change produced by influence. A determining factor believed by some to affect individual tendencies and characteristics understood to be caused by the positions of the stars and planets at the time of one's birth. Factors believed to be caused by the changing positions of the stars and planets in relation to their positions at the time of one's birth. To produce an effect on by imperceptible or intangible means; sway. To affect the nature, development, or condition of; modify. See Synonyms at affect1. under the influence Intoxicated, especially with alcohol.