Do up short red coat by mistake (9)
I believe the answer is:
refurbish
'do up' is the definition.
(thesaurus)
'short red coat by mistake' is the wordplay.
'short' means to remove the last letter.
'coat by' becomes 'fur' (fur is a kind of coat. I am not sure about the 'by' bit.**).
'mistake' becomes 'bish' (I've seen this in other clues).
'red' with its final letter taken away is 're'.
're'+'fur'+'bish'='REFURBISH'
Can you help me to learn more?
(Other definitions for refurbish that I've seen before include "Renovate, redecorate" , "Redecorate and brighten up" , "Clean up" , "Freshen up" , "Overhaul" .)