Run naked with redhead in small wood (6)
I believe the answer is:
streak
'run naked' is the definition.
(I've seen this before)
'redhead in small wood' is the wordplay.
'redhead' becomes 'r' (the head/first letter of 'red').
'in' means one lot of letters goes inside another.
'small' becomes 's' (abbreviation - e.g. clothes size).
'wood' becomes 'teak' (teak is a kind of wood).
's'+'teak'='steak'
'r' put inside 'steak' is 'STREAK'.
'with' acts as a link.
(Other definitions for streak that I've seen before include "Appear in the nude" , "run risk of arrest at sporting event?" , "Flash of colour - run naked" , "Run without clothes" , "feature of bacon" .)