It is hard to assess from screenshots what the problem is.
Try posting a video of what exactly you rotate and the result.

But generally rotating hand and keeping forearm static is humanly impossible.
If you wish you may decrease the forearm influence with ForearmTwist02 weight,
but it certainly has nothing to do with Upperarm bone influence (again, if you just rotate a Hand bone).

93% of original size (was 541x16) - Click to enlargethanks for the answer . I will try to explain more clearly. I want it when my wrist rotates. my hand remained motionless. because it's not right for my clothes. I understand . This is wrong with human anatomy. but for my clothes. I would like only my wrist to turn because my clothes are hanging off and it shouldn’t turn. you could take kevin and put him in a coat and turn his wirst and you will understand what i'm talking about 93% of original size (was 541x16) - Click to enlarge

OK, so you need to rotate a character limb inside the coat sleeve and keep it mostly static.
One thing for certain, you will not be able to achieve that with skin weights.

You might.. just might be able to do that with physics, but that is whole different story.
If your end production is outside of iClone, then even if you achieve acceptable results in iClone,
You have to find a way to "sneak" baked vertex animation produced by soft physics into your target app (maybe alembic).

I will try to put something together to show you basics later on... but it might be very tedious workflow and no guaranty for perfect visual.
And you also would need an iClone. CC would not help much.

If you rotate the hand using FK, then the forearm bone will not be rotated with it. So then you just need to adjust the weights of your coat sleeves so the hand bone has no influence. Of course you also need to make sure the sleeve is big enough to not get poke-through when you rotate the hand.
93% of original size (was 541x16) - Click to enlarge

yes you are right thank you. but is it possible to somehow leave the wrist motionless but at the same time move the character in the ik mod menu. because I can't do animations in the fk menu. i appreciate your work. but I want to fully understand. can I move my hand without moving my wrist in ik mode. Maybe I can somehow remake this particular bone into fk. while animating in ik mode?

Thanks a lot . moving in fk mode is not so convenient. but as I understand it, this is the only way to animate like this. thanks for your work!