Son packed and went off (8)
I believe the answer is:
Here is my best explanation:
'went off' is the definition.
The answer and definition can be both to do with motion as well as being past participle verbs.
Maybe they are linked in a way I don't understand?
'son packed' is the subsidiary indication.
'son' becomes 's'.
'packed' becomes 'crammed' ('cram' can be a synonym of 'pack').
'and' is the link.