1. organisms that live in or on another organism and benefit by deriving nutrients at the host’s expense
Usage: biology
2. people who habitually rely on or exploit others and give nothing in return
Usage: figurative; derogatory

Examples

• Fleas and ticks are common parasites found on dogs and cats.
• The doctor explained how intestinal parasites can cause digestive problems.
• Many tropical diseases are caused by parasites transmitted by mosquitoes.
• Marine biologists study parasites that affect fish populations.
• He called his lazy roommates parasites because they never paid rent.
• The wealthy family was surrounded by social parasites seeking favors.
• She refused to support financial parasites who wouldn’t work.