An act of employing or putting into play; use: the free exercise of intellect; the exercise of an option. The discharge of a duty, function, or office. Activity that requires physical or mental exertion, especially when performed to develop or maintain fitness: took an hour of vigorous daily exercise at a gym. A task, problem, or other effort performed to develop or maintain fitness or increase skill: a piano exercise; a memory exercise. An activity having a specified aspect: an undertaking that was an exercise in futility. A program that includes speeches, presentations, and other ceremonial activities performed before an audience: graduation exercises. To put into play or operation; employ: Proceed, but exercise caution. To bring to bear; exert: "The desire to be re-elected exercises a strong brake on independent courage\u201d ( John F. Kennedy). To subject to practice or exertion in order to train, strengthen, or develop: exercise the back muscles; exercise the memory. To put through exercises: exercise a platoon. See Synonyms at practice. To carry out the functions of: exercise the role of disciplinarian. To execute the terms of (a stock option, for example). To absorb the attentions of, especially by worry or anxiety. To stir to anger or alarm; upset: an injustice that exercised the whole community. To take exercise.