Repulsive joint found in prison, half of it missing (8)
I believe the answer is:
shocking
'repulsive' is the definition.
(thesaurus)
'joint found in prison half of it missing' is the wordplay.
'joint' becomes 'hock' (hock is a kind of joint).
'found in' indicates putting letters inside.
'prison' becomes 'Sing Sing' (US prison).
'half of it missing' means to take half the letters.
'singsing' halved is 'sing'.
'hock' inserted inside 'sing' is 'SHOCKING'.
(Other definitions for shocking that I've seen before include "offering a jar" , "Horrifying" , "Horrific (pink?)" , "Awful - ghastly" , "Causing disgust; very bad" .)