Busy person starts to chamfer hard wood (5)
I believe the answer is:
beech
'wood' is the definition.
(beech is a kind of wood)
'busy person starts to chamfer hard' is the wordplay.
'busy person' becomes 'bee' (I've seen this in other clues**).
'starts to' says to take the initial letters.
The first letters of 'chamfer hard' is 'ch'.
'bee'+'ch'='BEECH'
(Other definitions for beech that I've seen before include "Nut-bearing tree" , "Type of tree" , "Common forest tree" , "Copper or silver tree" , "Timber tree" .)