Coach finally accepted by team member, a fretful type (7)

'a fretful type' is the definition.
(someone who frets or whinges about things)

'coach finally accepted by team member' is the wordplay.
'finally' says to take the final letters.
'accepted by' is an insertion indicator.
'team member' becomes 'winger' (eg a winger in a football team).
The final letter of 'coach' is 'h'.
'h' going inside 'winger' is 'WHINGER'.