prey on

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

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

also prey upon something
to kill an animal in order to eat it Spiders prey on small flies and other insects. Seals often prey upon the same fish people are trying to catch.
Usage notes: said about animals that kill other animals for food
See also: on, prey

prey on somebody

also prey upon somebody
1. to commit a crime against someone Police are looking for street criminals who prey on tourists. Gangs that prey upon small business owners in the city's Chinatown may be spreading to the suburbs.
2. to have an effect on someone Guilt preyed on him for years after the accident.
Usage notes: sometimes said about something that has an effect on people's emotions: The ads prey on our fear of being alone.
See also: on, prey

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

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
References in classic literature ?
I suppose it is too insignificant to be noticed by the great Epeira, and is therefore allowed to prey on the minute insects, which, adhering to the lines, would otherwise be wasted.