WordWeb Online

1. Living by preying on other animals especially by catching living prey
   "the rapacious wolf";
   - predatory, raptorial, ravening, vulturine, vulturous
    
2. Excessively greedy and grasping
   "a rapacious divorcee on the prowl";
   - ravening, voracious
    
3. Devouring or craving food in great quantities
   "a rapacious appetite";
   - edacious, esurient, ravening, ravenous, voracious, wolfish

See also: acquisitive, aggressive, gluttonous