Noun. 1. refrigerant-any substance used to provide cooling (as in a refrigerator). substance-a particular kind or species of matter with uniform properties; shigella is one of the most toxic substances known to man.cryogen-a liquid that boils at below -160 C and is used as a refrigerant.. A substance, such as air, ammonia, water, or carbon dioxide, used to provide cooling either as the working substance of a refrigerator or by direct absorption of heat. 2. Medicine An agent used to reduce fever.
usually offensive: a person affected with extreme mental retardation. 2. : a foolish or stupid person. â idiot adjective. See idiot defined for English-language learners.
moron (plural morons) (informal) A stupid person; an idiot; a fool. (dated, originally) A person of borderline intelligence in the former classification of mental retardation, having an intelligence quotient of 50-69. The current medical term for having an IQ between 50 and 69 is mild mental retardation.