A fallacy is an error in reasoning that can occur in arguments and can lead to false or mistaken conclusions. Fallacies can take many forms, including invalid assumptions, misapplied evidence, misleading or irrelevant information, and a failure to address counterarguments. Fallacies are a common problem in arguments, both in everyday life and in more formal contexts such as political debates, legal proceedings, and scientific research.
Source: Walton, D. N. (1992). Plausible argument in everyday conversation. State University of New York Press.