Applies to a male who is filthy/dirty/unattractive in either physical appearance or personality, generally disgusting, unworthy, unsavory, waste of space. Often used when referring to an attractive woman's boyfriend by males who do not have attractive girlfriends or girlfriends at all.
"Man, I saw Heather the other day and she was with this grundlepatch. She could do way better! She could be dating me!"
(this word is spelled in any phonetic manner an individual finds appropriate)