A) Hi there, what’s up? What are you up to?
B) I’m not up to much. I am just reading.
What are you up for tonight ?
A) I’m not good enough to do this!
B) Oh yes, you are definitely up to (doing) it!
You are good enough to do this
A) Let’s go out tonight!
B) No I feel sick myself. I’m not up to it!
to not feel well enough
A) what are you up for tonight ?
B) I don’t care. It’s up to you .
It depends on you
Up for
I’m not up for that means I don’t want to do that.
I’m up for that means I want to do that.
I am not up for going out means I don’t want to go out.
I am not up to going out means I don’t feel well enough to go out.
I hope I’ve learned my lesson well.
Hi, Cevat.
In your example:
A) I’m not good enough to do this!
B) Oh yes, you are definitely up to do it!
I would leave out the "do" in the second sentence so it would read, "Oh yes, you are definitely up to it!"
This sounds more natural to me--at least in American English (on the west coast).
Another option would be, "Oh yes, you are definitely up to doing this!"
You are absolutely right.