Darling little accessory given to son (7)
I believe the answer is:
sweetie
'darling' is the definition.
(I've seen this before)
'little accessory given to son' is the wordplay.
'little' becomes 'wee' (similar in meaning).
'accessory' becomes 'tie' (I've seen this before).
'given to' says to put letters next to each other.
'son' becomes 's' (genealogical abbreviation for son).
'wee'+'tie'='weetie'
'weetie' put after 's' is 'SWEETIE'.
(Other definitions for sweetie that I've seen before include "Love" , "Darling" , "treasure?" , "Term of endearment" , "dear" .)