IMP ?? been playing 1000 years but can never remember what it is!

IMP ?? been playing 1000 years but can never remember what it is!
I have a serious brain cramp with IMP|||IMP=IMPortance.
It's used by the CPU in trades if I'm not mistaken. Outside of that it's a pretty useless ratings category.|||Its used for CPU determining trade values. Really worthless stat that didnt do a good job determining trade values.