Avuncular German discovered to be more generous (6)
I believe the answer is:
larger
'be more generous' is the definition.
('large' can be similar in meaning to 'generous')
'avuncular german discovered' is the wordplay.
'discovered' says the answer is hidden in the clue (remove the letters covering the answer in the clue).
'LARGER' is hidden within 'avuncular german'.
'to' acts as a link.
(Other definitions for larger that I've seen before include "Bigger, greater" , "bigger,greater" , "Comparatively big" , "Comparatively bigger" , "Greater in size" .)