prey on

prey (up)on (someone or something)

1. Of a predatory animal, to hunt and feed on another animal. Mountain lions have been coming down into town to prey on people's pets. You can tell that this bird preys upon insects by the shape of its beak.
2. To exploit, victimize, or take advantage of someone or something. There are many thieves and con-artists in the city who prey on unsuspecting tourists. These megacorporations are all too willing to prey upon consumers.
3. To cause one a lot of worry, concern, or anxiety, especially for a long period of time. I know that money issues have been preying on him ever since the company began issuing pay cuts. I really acted like a jerk on Friday night, and the guilt of it has been preying upon me all weekend long.
See also: prey
Farlex Dictionary of Idioms.

prey (up)on someone or something

Fig. to take advantage of someone or something. (See also prey on something. Upon is formal and less commonly used than on.) The people of that island prey on tourists and do not give them good treatment. I really don't want to seem to prey upon your kindness.
See also: on, prey

prey on something

[for an animal] to feed on another animal as a matter of habit or preference. Owls prey on mice. Many birds prey on snakes.
See also: on, prey
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

prey on

1. Plunder or pillage; also, make a profit at someone else's expense, victimize. For example, Vikings preyed on the coastal towns of England, or The rich have been preying on the poor for centuries. [Late 1500s]
2. Hunt, especially in order to eat, as in Their cat preys on all the rodents in the neighborhood. [c. 1600]
3. Exert a baneful or injurious effect, as in Guilt preyed on his mind. [c. 1700]
See also: on, prey
The American Heritage® Dictionary of Idioms by Christine Ammer.

prey on

v.
1. To hunt and kill something for food: Owls prey on mice.
2. To exploit or make a profit at the expense of someone; take advantage of someone: Pickpockets often prey on unsuspecting tourists.
3. To exert a harmful or injurious effect on something or someone: Guilt preyed on him, and eventually led him to confess.
See also: on, prey
The American Heritage® Dictionary of Phrasal Verbs.
See also:
  • prey (up)on (someone or something)
  • on the scent
  • on the scent (of something)
  • put (one) off the scent
  • put a dog off the scent
  • put off the scent
  • put someone off the scent
  • put/throw somebody off the scent
  • imprint on (someone or something)
  • snap (one's) head off