Son gaining weight — shock no longer (6)
I believe the answer is:
stonne
'shock no longer' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.
'son gaining weight' is the wordplay.
I cannot really see how this works, but
'son' could be 's' (genealogical abbreviation for son) and 's' is present in the answer.
'weight' could be 'tonne' (I've seen this before) and 'tonne' is present in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for stonne that I've seen is " shock no more".)