The Collaborative International Dictionary of English v.0.48:

Adjective \Ad"jec*tive\, v. t. [imp. & p. p. Adjectived; p.
   pr. & vb. n. Adjectiving.]
   To make an adjective of; to form or change into an adjective.
   [R.]
   [1913 Webster]

         Language has as much occasion to adjective the distinct
         signification of the verb, and to adjective also the
         mood, as it has to adjective time. It has . . .
         adjectived all three.                    --Tooke.
   [1913 Webster]