Question: One organism benefits at the expense of another?

Disambiguated questions and answers:
context: Cheating is a term used in behavioral ecology and ethology to describe behavior whereby organisms receive a benefit at the cost of other organisms. Cheating is common in many mutualistic and altruistic relationships. A cheater is an individual who does not cooperate (or cooperates less than their fair share) but can potentially gain the benefit from others cooperating. Cheaters are also those who selfishly use common resources to maximize their individual fitness at the expense of a group. Natural selection favors cheating, but there are mechanisms to regulate it.
question: One organism benefits at the expense of another in ethology?
short_answers: Cheating
wikipage: Cheating (biology)
context: In evolutionary biology, parasitism is a relationship between species, where one organism, the parasite, lives on or in another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has characterised parasites as "predators that eat prey in units of less than one". Parasites include protozoans such as the agents of malaria, sleeping sickness, and amoebic dysentery; animals such as hookworms, lice, mosquitoes, and vampire bats; fungi such as honey fungus and the agents of ringworm; and plants such as mistletoe, dodder, and the broomrapes. There are six major parasitic strategies of exploitation of animal hosts, namely parasitic castration, directly transmitted parasitism (by contact), trophically transmitted parasitism (by being eaten), vector-transmitted parasitism, parasitoidism, and micropredation.
question: One organism benefits at the expense of another in evolutionary biology?
short_answers: parasitism
wikipage: Parasitism

Long-form answers:
knowledge: content: Cheating is a term used in behavioral ecology and ethology to describe behavior whereby organisms receive a benefit at the cost of other organisms. Cheating is common in many mutualistic and altruistic relationships.[1] A cheater is an individual who does not cooperate (or cooperates less than their fair share) but can potentially gain the benefit from others cooperating.[2] Cheaters are also those who selfishly use common resources to maximize their individual fitness at the expense of a group.[3] Natural selection favors cheating, but there are mechanisms to regulate it.
wikipage: Cheating (biology)
content: Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life.
wikipage: Parasitism
long_answer: In ethology, cheating is a term used to describe behavior whereby organisms receive a benefit at the cost of other organisms, a concept that natural selection favors, but there are mechanisms to regulate it. Cheating is common in many mutualistic and altruistic relationships, where a cheater is an individual who does not cooperate, or cooperates less than their fair share, but can potentially gain the benefit from others cooperating. Cheaters are also those who selfishly use common resources to maximize their individual fitness at the expense of a group. In evolutionary biology, parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life.