Happy ignorance is not folly! (5)
I believe the answer is:
bliss
'happy ignorance' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'is not folly' is the wordplay.
I cannot quite see how this works, but
'is' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for bliss that I've seen before include "promise of afterlife" , "Sir Arthur --, British composer" , "One who wrote music" , "Intense happiness" , "of composing?" .)