With hard-wood, make a mess of it (4)
I believe the answer is:
hash
'a mess of it' is the definition.
I can't judge whether this definition defines the answer.
'with hard-wood' is the wordplay.
'with' means one lot of letters go next to another.
'hard' becomes 'h' (abbreviation used in pencil classifications).
'wood' becomes 'ash' (wood from an ash tree).
'h' put next to 'ash' is 'HASH'.
'make' acts as a link.
Can you help me to learn more?
(Other definitions for hash that I've seen before include "number provided by American" , "Mess; reheated meal" , "Minced meat and vegetables - a mess!" , "Recooked dish - quite a jumble" , "Mess; meat/potato dish" .)