Confine is quiet! (4,2)
I believe the answer is:
shut up
I believe this is a double definition.
'confine' is the first definition.
(shutting up is a kind of confining)
'quiet' is the second definition.
(thesaurus)
'is' is the link.
(Other definitions for shut up that I've seen before include "Imprisoned" , "Closely confined" , "in prison" , "Keep mum" , "Close your mouth!" .)