Parasitism (social offense)

Parasitism (social offense) is when someone takes advantage of other people or a group of people. It's like when a person acts like they need help, but they just want something for free. For example, if someone always comes to parties and your house and never brings anything, they're being a parasite because they're taking advantage of you, who are providing them with food and a place to have a good time, without giving anything back in exchange.