Bortnik is taken from a character from the Popeye cartoon. The Bortnik was the big ape-like woman who was friends with Olive. Bortnik is used to describe any woman who has similar feature, ie.. a woman who is big (not fat), has a big nose, greasy hair, large forhead, and scrapes her knuckles across the floor.
Chad: Hey there Will, look at that freakishly big woman over there. She looks familiar.
Will: That's a Bortnik. Are you ignorant or something? Now bend over and let me give you some man loving.