Don't reveal some foolish ideas (4)
I believe the answer is:
hide
'don't' is the definition.
Both the definition and answer are singular nouns.
Perhaps you can see an association between them that I can't see?
'some foolish ideas' is the wordplay.
'some' says the answer is hidden in the clue (some parts of the word are used).
'HIDE' is hidden in the letters of 'foolish ideas'.
'reveal' acts as a link.
Can you help me to learn more?
(Other definitions for hide that I've seen before include "Keep out of sight" , "Mammal's tough skin" , "Keep quiet" , "Animal retreat" , "Tanned skin of an animal" .)