Gift of support that's taken on a charity's case (6)
I believe the answer is:
legacy
'gift' is the definition.
(a legacy is gifted to future generations)
'support that's taken on a charity's case' is the wordplay.
'support' becomes 'leg' (leg is a kind of support).
'that's taken on' means one lot of letters go next to another.
'case' says to hollow out the word (remove centre letters).
'charity' with its centre taken out is 'cy'.
'leg'+'a'+'cy'='LEGACY'
'of' is the link.
(Other definitions for legacy that I've seen before include "Inheritance" , "Something bequeathed in will" , "Gift left in will" , "Willed gift" , "What is left to one in will" .)