Just son given hint (6)
I believe the answer is:
simply
'just' is the definition.
(synonyms)
'son given hint' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'given' says to put letters next to each other.
'hint' becomes 'imply' (I've seen this before).
's'+'imply'='SIMPLY'
(Other definitions for simply that I've seen before include "Merely, just" , "Without fuss" , "In a straightforward manner" .)