<unk>  is a pathogen's or microorganism's ability to cause damage to a host. In most contexts, especially in animal systems,<unk>  refers to the degree of damage caused by a microbe to its host. The pathogenicity of an organism—its ability to cause disease—is determined by its<unk>  factors. In the specific context of gene for gene systems, often in plants,<unk>  refers to a pathogen's ability to infect a resistant host. The noun<unk>  derives from the adjective<unk> ulent, meaning disease severity. The word<unk> ulent derives from the Latin word<unk> ulentus, meaning "a poisoned wound" or "full of poison." From an ecological standpoint,<unk>  is the loss of fitness induced by a parasite upon its host.<unk>  can be understood in terms of proximate causes—those specific traits of the pathogen that help make the host ill—and ultimate causes—the evolutionary pressures that lead to<unk> ulent traits occurring in a pathogen strain.
Virulence
Flatulence
Tenderness 
Acid-fastness
Fungating lesion
Baricity
Tickling
Necrophilia