One takes swag from place south of Exeter on vacation (9)

'one takes swag' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.

'place south of exeter on vacation' is the wordplay.
'place' becomes 'pl' (abbreviation used in postal addresses).
'south of' becomes 'under' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'on vacation' suggests removing the centre (after the inside letters have vacated the word).
'exeter' with its centre taken out is 'er'.
'pl'+'under'+'er'='PLUNDERER'

'from' is the link.

Can you help me to learn more?