1) Absolute adjective 2) An adjective used as a noun 3) Common noun 
In linguistics, an adnoun is a kind of lexical category. In English, it is a word that is usually an adjective, but is being used as a noun. The origin of the word is thought to date to around 1745-1755. Examples: Often these usages are simply identified as the noun form of the word. ==Alternatively== Adnoun is also considered to be an archaic ter...
adjective serving or used as a noun
• (n.) An adjective, or attribute.
Ad'noun` noun [ Prefix ad- + noun .] (Gram.) An adjective, or attribute. [ R.] Coleridge. 
[n] - an adjective used as a noun
noun an adjective used as a noun; ``meek` in `blessed are the meek` is an adnoun`
an adjective used as a noun, as meek in Blessed are the meek; absolute adjective.