Mark, in a part of the garden, shunned drink (9)
I believe the answer is:
abstained
'shunned drink' is the definition.
The answer and definition can be both to do with social activities as well as being past participle verbs.
Perhaps there's a link between them I don't understand?
'mark in a part of the garden' is the wordplay.
'mark' becomes 'stain' (synonyms).
'in' is an insertion indicator.
'a part of the garden' becomes 'abed' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'stain' going within 'abed' is 'ABSTAINED'.
Can you help me to learn more?
(Other definitions for abstained that I've seen before include "chose not to vote" , "was non-committal" , "kept dry" , "avoided port?" , "went on the wagon" .)