Like a family with no right to be joyful (6)
I believe the answer is:
elated
'be joyful' is the definition.
(synonyms)
'like a family with no right' is the wordplay.
'like a family' becomes 'related' (family members are related).
'with no' is a deletion indicator.
'right' becomes 'r' (common abbreviation).
'related' with 'r' taken out is 'ELATED'.
'to' acts as a link.
(Other definitions for elated that I've seen before include "Delighted, ecstatic" , "In high spirits, very pleased" , "Thrilled" , "Happy and exicited, overjoyed" , "Intensely delighted and proud" .)