In linguistics and social sciences, markedness is the state of standing out as nontypical or divergent as opposed to regular or common. In a marked–unmarked relation, one term of an opposition is the broader, dominant one. The dominant default or minimum-effort form is known as unmarked; the other, secondary one is marked. In other words, markedness involves the characterization of a "normal" linguistic unit against one or more of its possible "irregular" forms.

In linguistics, markedness can apply to, among others, phonological, grammatical, and semantic oppositions, defining them in terms of marked and unmarked oppositions, such as honest (unmarked) vs. dishonest (marked). Marking may be purely semantic, or may be realized as extra morphology. The term derives from the marking of a grammatical role with a suffix or another element, and has been extended to situations where there is no morphological distinction.

In social sciences more broadly, markedness is, among other things, used to distinguish two meanings of the same term, where one is common usage (unmarked sense) and the other is specialized to a certain cultural context (marked sense).

In psychology, the social science concept of markedness is quantified as a measure of how much one variable is marked as a predictor or possible cause of another, and is also known as Δp (deltaP) in simple two-choice cases. See confusion matrix for more details.