Irrelevant

Irrelevant is an adjective used to describe something that is not connected with or pertinent to the matter at hand. It characterizes information, arguments, evidence, or considerations that do not bear on the topic being discussed or do not affect the outcome.

Etymology: The word is formed by adding the prefix in- to relevant, which comes from Latin relevans, the present participle of relevare meaning to raise or lighten. The figurative sense of bearing on a matter developed in English over time, yielding the modern meaning of not bearing on the issue.

Usage: In everyday speech, labeling a point as irrelevant is a way to steer discussion back to the main issue. In law and formal debate, relevance is a criterion; evidence or arguments that do not relate to a contested issue are typically deemed irrelevant and may be excluded. In logic and rhetoric, an irrelevant conclusion or ignoratio elenchi is a fallacy in which the premises fail to support the conclusion.

Information processing and data analysis distinguish relevant from irrelevant features. In statistics and machine learning, removing irrelevant or noisy features can improve model performance. In search and recommendation systems, relevance is the criterion by which results are ranked; items deemed irrelevant to a user query are filtered or ranked lower.

See also: relevance, irrelevance, ignoratio elenchi, red herring.