Unclear VAR arrangement results in facetious swearing (10)
I believe the answer is:
vernacular
'facetious swearing' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'unclear var arrangement' is the wordplay.
'arrangement' indicates an anagram.
'unclear'+'var'='unclearvar'
'unclearvar' with letters rearranged gives 'VERNACULAR'.
'results in' is the link.
Can you help me to learn more?
(Other definitions for vernacular that I've seen before include "Local-style" , "Everyday language" , "Characteristic language" , "Native tongue - dialect" , "Native language" .)