A retarded individual who will do most anything due to the lack of common sense and pride.
Eating cat food on a dare, hugging and kissing an empty keg of beer, and acting like a chimp while sober would all be good examples of being a 'cumber'. Generally annoying most of the time, slurred speech is common in the person, usually uttering extremely stupid comments. Tell-tale sign of being a 'cumber'? Singing Simple Man after being asked to stop by friends.