Empty talk mostly painful for royal family (7)
I believe the answer is:
windsor
'for royal family' is the definition.
(Windsor is an example)
'empty talk mostly painful' is the wordplay.
'empty talk' becomes 'wind' (I've seen this in another clue).
'mostly' means to remove the last letter (most but not all of the word).
'painful' becomes 'sore' (similar in meaning).
'sore' with its last letter removed is 'sor'.
'wind'+'sor'='WINDSOR'
(Other definitions for windsor that I've seen before include "Knot type; royal castle" , "-chair; -knot; -castle" , "9 [HOUSE]" , "one such as Edward VIII" , "Berkshire castle" .)