New king in beer joint (5)
I believe the answer is:
ankle
'joint' is the definition.
(joint of the body)
'new king in beer' is the wordplay.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'king' becomes 'K' (abbreviation for king in chess).
'in' means one lot of letters goes inside another.
'beer' becomes 'ale' (type of beer).
'n'+'k'='nk'
'nk' going within 'ale' is 'ANKLE'.
(Other definitions for ankle that I've seen before include "Foot-leg connector" , "Part of the leg between the foot and the shin" , "Major foot joint" , "Joint between foot and leg" , "Leg-joint" .)