A term used mostly by kite surfers to describe a ridiculously fit female. Can be split down to just gutter or have words that ryhme with gutter added at the beginning, such as utter gutter filth. Normally used to describe a chick who looks as good as she does dirty and that any time spent in bed with her would be gutter filth.
"Hey Dom, have you seen that gutter filth chick over there?"
"Yeah Rou, she is utter gutter filth!"