snol·ly·gos·ter (snŏl'ē-gŏs'tər) n.
Slang One, especially a politician, who is guided by personal advantage rather than by consistent, respectable principles.
[Perhaps alteration of snallygaster, a mythical beast said to prey on poultry and children, perhaps from Pennsylvania Dutch schnelle geeschter : Middle High German snēl, quick (from Old High German) + Middle High German geist, spirit (from Old High German).]