Vice rings close to you? Say no more (4,2)
I believe the answer is:
clam up
'say no more' is the definition.
(to clam up is to stop talking due to nerves)
'vice rings close to you?' is the wordplay.
'vice' becomes 'clamp' (I've seen this before).
'rings' is an insertion indicator (some letters are ringed or contained by others).
'close to' suggests the final letters (the 'close' to the word).
The last letter of 'you' is 'u'.
'clamp' enclosing 'u' is 'CLAM UP'.
(Other definitions for clam up that I've seen before include "Go silent" , "Refuse to speak" , "Abruptly stop talking (colloq.)" , "Stop giving out" , "Keep mum" .)