Ma·lume (ma' loom air) n. 1. a. The brother of one's mother or father. b. The husband of a sibling of one's mother or father. 2. Used as a form of address for an older man, who has failed in life and he has nothing going for him except shooting other people's dreams by abusing the respect you give him since they're older and by saying shit like what u doing ain't gona happen to kill your spirit . 3. A kindly counselor. 4. Slang A pawnbroker. 5. Uncle Uncle Sam