Fair and generous to celebrate sheltering harbour (8)
I believe the answer is:
sporting
'fair and generous' is the definition.
(I've seen this before)
'celebrate sheltering harbour' is the wordplay.
'celebrate' becomes 'sing' (I've seen this before).
'sheltering' indicates putting letters inside.
'harbour' becomes 'port' (I've seen this before).
'sing' enclosing 'port' is 'SPORTING'.
'to' is the link.
(Other definitions for sporting that I've seen before include "Able to take defeats in good part" , "Diver's point of departure" , "Fair and generous" , "game" , "Fair (chance)" .)