Permit to break the silence (7)
I believe the answer is:
license
'permit' is the definition.
(I know that permit can be written as license)
'break the silence' is the wordplay.
'break' indicates anagramming the letters.
'silence' with letters rearranged gives 'LICENSE'.
'to' acts as a link.
(Other definitions for license that I've seen before include "Authorise to sell in silence" , "Allow" , "Authorise (something)" , "Entitle" , "Grant official permit to sell or trade" .)