prey on (someone)

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.

• by hook or by crook
• by leaps and bounds
• by mistake
• by no means
• by rote
• by the back door
• by the book
• by the dozen
• by the name
• by the name of
• by the same token
• by the seat of pants
• by the seat of your pants
• by the skin of teeth
• by the skin of your teeth
• by the sweat of brow
• by the sweat of your brow
• by the way
• by virtue of
• by virtue of something
• by word of mouth
• cack-handed
• call a halt
• call a halt to
• call a halt to something