Son walked away, dazed (6,3)
I believe the answer is:
spaced out
'dazed' is the definition.
(I've seen this in another clue)
'son walked away' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'walked' becomes 'paced' (pacing is a kind of walking).
'away' becomes 'out' (similar in meaning).
's'+'paced'+'out'='SPACED OUT'
(Other definitions for spaced out that I've seen before include "High on drugs" , "Placed well apart - unaware of one's surroundings" , "in a dazed state" , "Not quite all there?" , "Separated" .)