The Collaborative International Dictionary of English v.0.48:

deconstructionism \de`con*struc"tion*ism\
   (d[-e]`k[u^]n*str[u^]k"sh[u^]n*[i^]z'm), n.
   Same as decontruction[1].

   Syn: deconstruction.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

deconstructionism
    n 1: a philosophical theory of criticism (usually of literature
         or film) that seeks to expose deep-seated contradictions in
         a work by delving below its surface meaning [syn:
         deconstruction, deconstructionism]