A parasite is an organism which gets all of its energy from another organism without giving anything back. Examples of parasites include animals who suck blood, such as ticks, and plants like mistletoe. Successful parasites leave their hosts alive, but sometimes the parasite makes the host sick.
It is a type of symbiosis meaning the relationship between two organisms when one benefits but the other is harmed
If you are meaning Parasitism, it is a type of symbiotic relationship between organisms in which one organism (the parasite) benefits and the other (the host) is harmed.
Parasitism refers to one type of interspecies relationships. In parasitism, the parasitic species gains benefit from the host, which is harmed by the relationship.
Parasitic is a type of relationship that thrives in exploiting or relying on others. In such a relationship, the parasite is the one that benefits from the host.