Source : Webster's Revised Unabridged Dictionary (1913)

Sonneteer \Son`net*eer"\, n.
   A composer of sonnets, or small poems; a small poet; --
   usually in contempt.

         What woful stuff this madrigal would be In some starved
         hackney sonneteer or me!                 --Pope.

Sonneteer \Son`net*eer"\, v. i.
   To compose sonnets. --Lowell.

Source : WordNet®

sonneteer
     n : a poet who writes sonnets