It's been carelessly said to associate with sin (3)
I believe the answer is:
bin
'sin' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe you can see an association between them that I don't see?
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for bin that I've seen before include "Graves seen here" , "Common receptacle for household waste" , "Domestic receptacle for rubbish" , "Where to put rubbish" , "wine storage facility" .)