A purveyor of crap. One who seeks to persuade another that his or her self-serving ideas should be adopted, despite their crappiness.
"Moritz, you craphound! Leave me alone!" -- Burt Lancaster, "Local Hero", 1983
Someone who relishes crap in any form. A craphound is someone who has an intense desire for anything that is cheap, dirty, of poor quality, etc.
"I can't believe he eats fast food everyday."
"Yeah, he's a real craphound."