Hard wood? Magnolia, for starters (4)
I believe the answer is:
firm
'hard' is the definition.
('firm' can be similar in meaning to 'hard')
'wood? magnolia for starters' is the wordplay.
'wood?' becomes 'fir' (fir is a kind of wood).
'for starters' suggests taking the first letters.
The initial letter of 'magnolia' is 'm'.
'fir'+'m'='FIRM'
(Other definitions for firm that I've seen before include "Resolute kind of business" , "Steady and unyielding, like business organisation" , "corporation?" , "Organization" , "Steady and resolute" .)