Fine to move, avoiding black stuff (5)
I believe the answer is:
fudge
'stuff' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'fine to move avoiding black' is the wordplay.
'fine' becomes 'f' (abbreviation e.g. condition of old coins, books).
'to move' becomes 'budge' (to budge is to move slightly).
'avoiding' indicates named letters should be taken away.
'black' becomes 'b' (abbreviation as in pencil classifications).
'budge' with 'b' taken out is 'udge'.
'f'+'udge'='FUDGE'
Can you help me to learn more?
(Other definitions for fudge that I've seen before include "Sweet - evasion" , "Something sweet" , "Falsify - soft sweet" , "Soft buttery sweet" , "humbug" .)