Outwit states that you need a clear line of fire.
If that line of fire passes thru hindering terrain, can you still use outwit.
And if so, where in the rules does it say that thru hindering is still a clear line of fire for outwit.
thanks!

Since firing through hindering terrain is permitted it's given that it's a clear line of fire. Since you're not making an attack and attempting to produce damage it simply comes down to a question of whether or not one can see the target and if it's 10 or fewer squares away.

Someone will probably quote chapter and verse, but I don't have it (nor the time) handy right now.

Yes you can and nowhere does it say that, at least not directly. From the section under ranged combat attacks:
"Before making a ranged combat attack, you must determine if the attacker has a clear line of fire to the target and if the target is within range. To determine if there is a clear line of fire, use any straight edge or draw an imaginary line from the center of the attacker's square to the center of the target's square. Line of fire is blocked and the attack cannot be made if the imaginary line passes through a square that contains a character other than the attacker or the target, or if the line of fire crosses blocking terrain. Soaring characters block line of fire only if the line is being drawn to or from another soaring character. A line of fire that passes between two characters, even on an exact diagonal, is considered blocked."

So there you have the definition of "clear line of fire" and there is no mention of hindering terrain.

Just watch out for stealth, since someone in stealth can never be outwitted :-p

Thank you everyone for your answers.