Don't air (7)
I believe the answer is:
refrain
This could be a double definition.
'don't' is the first definition.
Both the answer and definition are singular nouns.
Maybe you can see an association between them that I can't see?
'air' is the second definition.
(thesaurus)
Can you help me to learn more?
(Other definitions for refrain that I've seen before include "tune" , "Chorus; keep away (from)" , "Cease - repeated phrase" , "burden" , "Main theme" .)