Concert ain't yet featured 'No Doubt (9)
I believe the answer is:
certainty
'doubt' is the definition.
The definition and answer can be both human attributes as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'concert ain't yet featured 'no' is the wordplay.
'CERTAINTY' is hidden within the letters.
However, I am uncertain how this is indicated.
Can you help me to learn more?
(Other definitions for certainty that I've seen before include "Conviction" , "It's inevitable" , "State of being sure" , "Banker" , "Cinch" .)