Small son, delicate (6)
I believe the answer is:
slight
'small' is the definition.
(thesaurus)
'son delicate' is the wordplay.
'son' becomes 's'.
'delicate' becomes 'light' ('light' can be similar in meaning to 'delicate').
's'+'light'='SLIGHT'
(Other definitions for slight that I've seen before include "Affront of delicate sort" , "Small, snub" , "Inconsiderable - insult" , "cut" , "A disrespectful reference - not great" .)