Trim back on hard humour (5)
I believe the answer is:
mirth
'humour' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'trim back on hard' is the wordplay.
'back' says the letters should be written in reverse.
'on' means one lot of letters go next to another.
'hard' becomes 'h' (abbreviation used in pencil classifications).
'trim' reversed gives 'mirt'.
'mirt'+'h'='MIRTH'
Can you help me to learn more?
(Other definitions for mirth that I've seen before include "funny feeling" , "Amusement - jollity" , "Laughter" , "Hilarity" , "Merriment" .)