What is sport? What is sport? Physical activity that is governed by a set of rules or customs and often engaged in competitively.A particular form of this activity.An activity involving physical exertion and skill that is governed by a set of rules or customs and often undertaken competitively.An active pastime; recreation.Mockery; jest: He made sport of his own looks. An object of mockery, jest, or play: treated our interests as sport. A joking mood or attitude: She made the remark in sport. One known for the manner of one's acceptance of rules, especially of a game, or of a difficult situation: a poor sport. Informal One who accepts rules or difficult situations well.Informal A pleasant companion: was a real sport during the trip. Informal A person who lives a jolly, extravagant life.Informal A gambler at sporting events.Biology An organism that shows a marked change from the normal type or parent stock, typically as a result of mutation.Maine See summercater. See Regional Note at summercater.Obsolete Amorous dalliance; lovemaking.To play or frolic.To joke or trifle.Biology To mutate.To display or show off: "His shoes sported elevated heels” ( Truman Capote). Of, relating to, or appropriate for sports: sport fishing; sports equipment. Designed or appropriate for outdoor or informal wear: a sport shirt.