A sharp twist in relations with king (4)
I believe the answer is:
kink
'a sharp twist' is the definition.
(a kink is a twist or knot)
'relations with king' is the wordplay.
'relations' becomes 'kin' (I've seen this before).
'with' is a charade indicator (letters next to each other).
'king' becomes 'K' (abbreviation for king in chess).
'kin'+'k'='KINK'
'in' is the link.
(Other definitions for kink that I've seen before include "Crimp" , "Sharp twist in wire or hair, perhaps" , "Constricting bend in pipe" , "Hitch" , "gasp" .)