Confine within bowels of vacant dungeons (4)
I believe the answer is:
cage
'confine within' is the definition.
'cage' can be an answer for 'confine' (caging is a kind of confining). I am not certain of the 'within' bit.
'bowels of vacant dungeons' is the wordplay.
'bowels' becomes 'cola' (colon is a kind of bowel).
'of vacant' suggests removing the centre (I've seen 'vacant' mean this (a vacant or emptied out form of the word)).
'dungeons' becomes 'ge' (I am not sure about this - if you are sure you should believe this answer much more).
'cola' with its centre removed is 'ca'.
'ca'+'ge'='CAGE'
Can you help me to learn more?
(Other definitions for cage that I've seen before include "Imprison, confine" , "One famous for creating silence" , "Barred container" , "Confine -- US composer, d. 1992" , "American composer with centenary this year" .)