Coal left in fire (5)
I believe the answer is:
slack
'coal' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'left in fire' is the wordplay.
'left' becomes 'l' (common abbreviation).
'in' means one lot of letters goes inside another.
'fire' becomes 'sack' (dismiss someone from their job).
'l' going within 'sack' is 'SLACK'.
Can you help me to learn more?
(Other definitions for slack that I've seen before include "Powdery coal" , "skive" , "Lazy and careless" , "Not taut" , "Idle and disinclined to work" .)