A shortened term for, "know what I'm sayin'?"
Often used to enhance informal conversation.
-I have to go fill a hole in my backyard.
-I'll fill your hole in my backyard, nawmsayin'?
Slang in the interweb world for, "Know what I'm sayin?"
Person 1 - I have a Honda Civic.
Person 2 - Honda Civics are gay, nawmsayin.