(1) A cad, rogue or bounder. A highly-functioning, charismatic sociopath who has a purely instrumental view of others. Treats women like objects and vice versa.
(2) A medium-sized shark in the genus Mustelae.
(1) "You cheated on your Cambridge finals, sold crack to your aunt, gave the hiv and the herp to many student nurses, and later became the chairman of an investment bank. What kind of man are you, for God's sake?"
"I'm a smooth-hound. That's how we roll."
(2) "The smooth-hound is a very ordinary shark; its name is the most interesting thing about it. Smooth-hound."
When someone with no teeth gives you a blowjob,
Named after the Australian Gummy Shark and reading too much Hentai
"Whew!~ My partner gave me an Aussie Smooth Hound last night."