Wordnet 3.0
ADJECTIVE (1)
1. 
 not fissile; 
The Collaborative International Dictionary of English v.0.48:
nonfissile \nonfissile\ adj.
   not fissile. Opposite of fissile.
   [WordNet 1.5]
WordNet (r) 3.0 (2006):
nonfissile
    adj 1: not fissile [ant: fissile]