The Collaborative International Dictionary of English v.0.48:

Criticaster \Crit"ic*as`ter\ (kr[i^]t"[i^]k*[a^]s`t[~e]r), n.
   A contemptible or vicious critic.
   [1913 Webster]

         The rancorous and reptile crew of poeticules, who
         decompose into criticasters.             --Swinburne.
   [1913 Webster]