Zoology. preying upon other organisms for food.
of, pertaining to, or characterized by plunder, pillage, robbery, or exploitation: predatory tactics.
engaging in or living by these activities: predatory bands of brigands.
excessive or exploitive in amount or cost, as out of greed or to take advantage of consumers or patrons: predatory pricing.
acting with or possessed by overbearing, rapacious, or selfish motives: He was cornered at the party by a predatory reporter.
2, 3. rapacious.
is a TOEFL word you need to know.
So is particle. Does it mean: