When the odds are not level, it's rough! (6)
I believe the answer is:
uneven
'rough' is the definition.
(associated in meaning)
'when the odds are not level' is the wordplay.
I cannot really see how this works, but
'when' could be 'e' (I've seen this in other clues) and 'e' is present in the answer.
'not' could be 'un' (prefix meaning 'not') and 'un' is located in the answer.
The remaining letters 'ven' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'it's' acts as a link.
Can you help me to learn more?
(Other definitions for uneven that I've seen before include "Ill-matched - irregular" , "Not uniform or smooth" , "Rough and irregular" , "Inconsistant in quality" , "Rough, bumpy" .)