Delight seeing good boy study (7)
I believe the answer is:
gladden
'delight' is the definition.
(I've seen this before)
'good boy study' is the wordplay.
'good' becomes 'g' (abbreviation).
'boy' becomes 'lad' (informal term for boy).
'study' becomes 'den' (term for a study or office).
'g'+'lad'+'den'='GLADDEN'
'seeing' is the link.
(Other definitions for gladden that I've seen before include "Make joyful" , "please" , "Delight" , "raise spirits" , "Lift (the heart)" .)