Poles in characteristic movement (7)
I believe the answer is:
transit
'movement' is the definition.
(transit is a kind of movement)
'poles in characteristic' is the wordplay.
'poles' becomes 'ns' (North and South poles).
'in' means one lot of letters goes inside another.
'characteristic' becomes 'trait' (I've seen this before).
'ns' going within 'trait' is 'TRANSIT'.
(Other definitions for transit that I've seen before include "Start in for the process of being conveyed" , "Passage of a planet across the sun's disc" , "Pass across/through" , "Act of passing across" , "Pass through; van" .)