unclear

Unclear is an adjective that means not easily understood or interpreted; lacking clarity; vague or ambiguous in its meaning or presentation. It can describe language, instructions, data, arguments, or conclusions when meaning is obscured or insufficient information prevents confident interpretation.

In everyday use, someone may say a sentence is unclear, a plan is unclear, or the results are unclear. In formal contexts, the term often flags intentional or required clarification, as in guidelines that require clearer definitions or more precise measurement.

Unclear information may arise from poor wording, omitted assumptions, contradictory details, or insufficient context.

Unclear is related to, but distinct from, ambiguity and vagueness. Ambiguity refers to content with multiple possible interpretations; vagueness refers to a lack of precise boundaries or thresholds; obscure and opaque refer to difficulty due to complexity or concealment; incoherent refers to logical or structural lack of coherence. A statement can be unclear without being inherently ambiguous if it lacks proper antecedents or has confusing syntax.

Etymology-wise, unclear is formed from the prefix un- plus clear, a standard English construction dating back to the Middle English period.

See also: ambiguity, vagueness, clarity, coherence, miscommunication.