6. derisive mockery or the object of such mockery: to make sport of someone. 7. someone or something that is controlled by external influences: the sport of fate. 10. informal a person who leads a merry existence, esp a gambler: he's a bit of a sport.
Rust is a fungal disease that occurs on turf grasses when their growth is slowed. This usually happens in late summer or early fall, during periods of dry weather or when the grass is low on nitrogen. Lawn rust can weaken the vigor of the grass and open it to other diseases and turf problems.
4. any growth, habit, or agency tending to injure or impair the mind, abilities, etc. 5. a. any of several diseases of plants, characterized by reddish, brownish, or black pustules on the leaves, stems, etc., caused by fungi of the order Uredinales. b. Also called rustâ² fun`gus. a fungus causing this disease.