He was a very fair man (6)
I believe the answer is:
adonis
'man' is the definition.
(adonis is a kind of man)
'he was a very fair' is the wordplay.
I cannot quite see how this works, but
'he' could be 'don' and 'don' is found in the answer.
'was' could be 'is' (being is a kind of being) and 'is' is found within the answer.
'a' is found in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for adonis that I've seen before include "A very handsome legendary Greek" , "one deemed to be beautiful" , "Handsome youth - said no (anag)" , "Handsome youth (Gr.)" , "ideal man" .)