secret approval vs approval

secret approval and approval both are nouns.

Word	Noun	Adjective	Verb	Adverb
secret approval	Yes	No	No	No
approval	Yes	No	No	No

As nouns, approval is a hypernym of secret approval; that is, approval is a word with a broader meaning than secret approval:

Other hypernyms of secret approval include commendation.

secret approval (noun)	approval (noun)
(law) tacit approval of someone's wrongdoing	the formal act of approving
	a message expressing a favorable opinion
	a feeling of liking something or someone good
	acceptance as satisfactory