Wiktionary
vb. 1 (context transitive English) To eat (as prey). 2 (context transitive English) To exploit or victimize.
Usage examples of "prey on".
I can under such circumstances see no reason to doubt that the swiftest and slimmest wolves would have the best chance of surviving, and so be preserved or selected, -- provided always that they retained strength to master their prey at this or at some other period of the year, when they might be compelled to prey on other animals.
You can be careful to take only the guilty, only the ones who prey on others.
What I did was prey on their weakness for obfuscation and self-indulgence.
Unfortunately, that ease of adaptation had been a twoedged sword, for Manticore had proven one of the very few planets capable of producing an indigenous disease that could prey on humanity.
Two million years after the uneasy truce imposed by the dinosaurs' death, the mammals had started to prey on each other.