Runner who's taken off? (8)
I believe the answer is:
streaker
'runner' is the definition.
(I have seen 'Naked runner' mean 'streaker' so perhaps 'runner' could also mean 'streaker')
I don't understand the remainder of the clue.
(Other definitions for streaker that I've seen before include "he barely covers the distance" , "One who runs naughtily nude in public" , "Person who runs naked through a public place" , "Rat reeks (anag.)" , "One making a dash without clothes" .)