1. Lacking definiteness or precision, or not easily understood: It appeared the vagueness of the policy options in Mayor Hillman's speech was deliberate.
2. A communication pattern involving the use of loose associations that lead to ambiguity and confusion in communication: President Black spoke in what appeared to be a deliberate pattern of vagueness which was short of reality.
3. The phenomenon that the meaning of an expression is not exactly determined, as a result of the impreciseness of the language that is used: In "John is tall", the meaning of the adjective "tall" shows vagueness, or is unclear, in the sense that the precise degree of tallness is not specific.

Vagueness should not to be confused with "ambiguity" (an unclear or a double meaning), even though the two are not always clearly distinguishable by some speakers or writers.