Usually it is uses of words, not words in themselves, that are properly called vague.

169-92. Proceedings of the Aristotelian Society. Fann K.

Prior to Austin the attention of linguistic and analytic philosophers had been directed almost exclusively to statements assertions and propositions — to linguistic acts that (at least in theory) have truth-value. John Langshaw "J. " Austin (26 March 1911 – 8 February 1960) was a British philosopher of language.