Giving to the poor but cautious about it (7)
I believe the answer is:
charity
'giving to the poor' is the definition.
(giving to those less fortunate)
'cautious about it' is the wordplay.
'cautious' becomes 'chary' (similar in meaning).
'about' indicates putting letters inside.
'chary' going around 'it' is 'CHARITY'.
'but' is the link.
(Other definitions for charity that I've seen before include "Giving to the needy" , "Almsgiving" , "Gifts to the needy" , "Love" , "Miss Pecksniff, for example" .)