Bad end involves a king in the altogether (5)
I believe the answer is:
naked
'in the altogether' is the definition.
(I've seen this in another clue)
'bad end involves a king' is the wordplay.
'bad' indicates an anagram.
'involves' is an insertion indicator.
'king' becomes 'K' (chess abbreviation).
'end' anagrammed gives 'ned'.
'a'+'k'='ak'
'ned' placed around 'ak' is 'NAKED'.
(Other definitions for naked that I've seen before include "Bare" , "Au naturel" , "Blatant" , "Without protection" , "Unclad" .)