justifier

Justifier is a noun formed from the verb justify. It can refer to a person who provides justification for an action or belief, or to a device, method, or program that performs justification in a particular domain.

In typography and typesetting, a typographic justifier is a component or algorithm that adjusts word and letter spacing to align text along both the left and right margins. Modern justifiers use hyphenation, variable spacing, and microtypographic adjustments to improve evenness of density and line length while minimizing visual rivers and awkward breaks. The effectiveness of a text justifier depends on quality of the underlying algorithms and the languages involved, as different scripts require different spacing rules and hyphenation patterns.

In computing and artificial intelligence, a justifier can refer to a tool or component that provides justification or rationale for a decision, recommendation, or conclusion. This may involve generating natural language explanations, presenting supporting evidence, or outlining the logical steps that led to a result. In rule-based systems, a justifier returns the justification for a given inference; in explainable AI, it aids user understanding and trust by making outcomes more transparent.

In philosophy, rhetoric, and legal contexts, a justifier is any reason, evidence, or argument used to defend or legitimize a claim, action, or policy. The term emphasizes the role of justification as a prerequisite for acceptance or compliance rather than as an intrinsic truth.

See also: justification, justification logic, text alignment.