I need to decribe Montag as briefly as possible. can someone help me?

In as few words as possible, Guy Montag from Bradbury's Fahrenheit 451 is:

Shy, awkward with people, discontented, unhappy, unsatisfied, inquisitive, curious, brave, and open to new ideas.

Discontented means he is not content with his life.  He is unsatisfied in the sense that he knows there must be something more to life and existence than he has.  Inquisitive is similar to curious but perhaps a little stronger.  And he wants to learn and be exposed to new ideas. 

Montag has many personality traits, but I hope what I've listed above helps you out.