Wordnet 3.0
ADJECTIVE (1)
1. 
 not easily solved; 
- Example: "an apparantly insolvable problem"- Example: "public finance...had long presented problems unsolvable or at least unsolved"- C.L.Jones[syn: insolvable, unsoluble, unsolvable, unresolvable]
The Collaborative International Dictionary of English v.0.48:
Unsolvable \Unsolvable\
   See solvable.
WordNet (r) 3.0 (2006):
unsolvable
    adj 1: not easily solved; "an apparantly insolvable problem";
           "public finance...had long presented problems unsolvable
           or at least unsolved"- C.L.Jones [syn: insolvable,
           unsoluble, unsolvable, unresolvable]