Concert piece that can't fail (4)
I believe the answer is:
cert
'piece that can't fail' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'concert' is the wordplay.
'CERT' is hidden within the letters.
But, I'm not sure how this is indicated.
Can you help me to learn more?
(Other definitions for cert that I've seen before include "Sure thing (that could be dead!)" , "One sure to win (slang)" , "Infallible bet (slang)" , "Safe bet" , "Inevitable event" .)