Gidrovlicheskiy
Someone whose motivations are persistently ambiguous and might be untrustworthy on the whole. The term is believed to have originated from that of a shifty Soviet scoundrel whom often auctioned himself off to overweight Italian sewage maintenance workers for reasons unknown.
"I just realized last night that David has been purloining all my finely smoked sandwich meats and padding the inside of his tighty whities with them. A true Gidrovlicheskiy, that feller is."