to harm somebody who is weaker than you, or make use of them in a dishonest way to get what you want
شکار کردن (به مفهوم استعاری), از کسی سوء استفاده کردن, بهرهکشی کردن, سو استفاده کردن, ظلم کردن
Bogus social workers have been preying on old people living alone.