Vermin is a term given to animals which are considered by humans to be pests or nuisances, most associated with the carrying of disease. Disease-carrying rodents and insects are the usual case but the term can also apply to larger animals, on the basis that they exist out of ecological balance with their environment, consuming excessive resources.

The term is also used as an extremely pejorative characterization of a particular class or group of people as being inferior and subhuman. Application of the term can be wide, having been applied over the centuries (in different languages) to various groups, and its use is usually based on a perception that the target group's views are "disease-like," or that such groups exist out of sociological balance with the common society.

Out of balance

Introduced species can develop into vermin in the regions where they were introduced if they find favourable living conditions, and if they face few or no natural enemies there. In such cases, humans often choose to fill the role of the predator to limit the danger to nature. A prime example of vermin are goats on Galapagos. Rats are common urban and suburban vermin.