The Collaborative International Dictionary of English v.0.48:
Belletristic \Bel`le*tris"tic\, Belletristical \Bel`le*tris"tic*al\, a. Occupied with, or pertaining to, belles-lettres. "An unlearned, belletristic trifler." --M. Arnold. [1913 Webster]WordNet (r) 3.0 (2006):
belletristic adj 1: written and regarded for aesthetic value rather than content