"`meek' in `blessed are the meek' is an adnoun.    From Wordnet, Princeton University. 

It is not, in all cases, easy to determine to which of these classes an adnoun should be referred.    From Wordnik.com.  [English Grammar in Familiar Lectures] Reference

The adnoun, or adjective.    From Wordnik.com.  [Specimens of the Table Talk of Samuel Taylor Coleridge] Reference