Predatory
Part of speech: adjective
Definition: Of, or relating to a predator. Living by preying on other living animals. Exploiting or victimizing others for personal gain.
Example sentence: The characters you refer to as predatory and unsavory are useful. They're the ones who make a novel into a thriller. They're active, and most of the common virtues, the signs of a good person, are not.
Rapacious
Part of speech: adjective
Definition: Voracious; avaricious.Given to taking by force or plundering.Said of an animal, usually a bird, that subsists off of live prey.