Neither going up nor down? That's fair (2,3,5)
I believe the answer is:
on the level
'fair' is the definition.
(I've seen this before)
'neither going up nor down?' is the wordplay.
I cannot really see how this works, but
'going' could be 'on' (both can mean functioning or activated) and 'on' is found in the answer.
This explanation may well be incorrect...
'that's' acts as a link.
Can you help me to learn more?
(Other definitions for on the level that I've seen before include "Fair; honestly speaking" , "Honest, truthful (colloq.)" , "Some horse racing is" , "Honest - genuine" , "No tipping" .)