Unspoken but understood (5)
I believe the answer is:
tacit
'unspoken but understood' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tacit that I've seen before include "Implied without being put into words" , "Understood without being directly expressed" , "Silent - understood" , "without speaking" , "Implied without being said" .)