Stop being flexible when naked (3)
I believe the answer is:
end
'stop' is the definition.
(synonyms)
'flexible when naked' is the wordplay.
'flexible' becomes 'bendy' (able to bend).
'when naked' says to take the centre.
The centre of 'bendy' is 'END'.
'being' is the link.
(Other definitions for end that I've seen before include "Cesation, conclusion" , "scrap" , "Unyielding" , "Exterminate - object" , "Climax" .)