Country fellow opening note (4)
I believe the answer is:
mali
'country' is the definition.
(I know that Mali is a country)
'fellow opening note' is the wordplay.
'fellow' becomes 'al' (man's name).
'opening' is an insertion indicator (some letters open a gap in others).
'note' becomes 'mi' (as in 'do re mi').
'al' inserted into 'mi' is 'MALI'.
(Other definitions for mali that I've seen before include "Send mail out to Africa" , "Country of West Africa" , "Indian gardener; African republic" , "Land" , "part of Africa" .)