They're drawn with authority by Poles (5)
I believe the answer is:
plans
'they're drawn' is the definition.
The definition suggests an adverb but the answer is not.
'with authority by poles' is the wordplay.
'with' means one lot of letters go next to another.
'authority by' becomes 'pla' (I can't justify this - if you can you should give a lot more credence to this answer).
'poles' becomes 'NS' (north and south poles).
'pla' next to 'ns' is 'PLANS'.
Can you help me to learn more?
(Other definitions for plans that I've seen before include "Aims" , "Intentions or drawings" , "Schemes; diagrams" , "Designs" , "Stratagems" .)