Some are more or less accurate, but running is definately not the opposite of walking.
I will try it one last time with a different take:
I think we agree that you can walk and that you can also walk fast, right?
We can also agree that walking fast and running is not the same, right?
So if running is the opposite of walking because its faster, is walking fast also the opposite of walking because its faster than walking?
Actually the funniest part is that I initially explained it in a ways I would do with a 6 year old. "Not walking is the opposite of walking". And not walking can also be the words listed above.
Explained like you are 6 year old and you still stick to your claim. Like a 6 year old actually.