Looks a lot like it'd come from the same root as venereal (from a different sort of hunting...), but it doesn't.

This is not quite a cleave/cleave situation. They do indeed come from the same root if you go back far enough, at least according to the AHD.

http://www.bartleby.com/61/22/V0052200.html

http://www.bartleby.com/61/23/V0052300.html

They diverged pretty quickly.