let on vs tattle

let on is not a noun while tattle is a noun.

Word	Noun	Adjective	Verb	Adverb
let on	No	No	Yes	No
tattle	Yes	No	Yes	No

As verbs, tattle is a hyponym of let on; that is, tattle is a word with a more specific, narrower meaning than let on:

let on: make known to the public information that was previously known only to a few people or that was meant to be kept a secret
tattle: divulge confidential information or secrets

let on (noun)	tattle (noun)
	disclosing information or giving evidence about another

let on (verb)	tattle (verb)
make known to the public information that was previously known only to a few people or that was meant to be kept a secret	speak (about unimportant matters) rapidly and incessantly
	divulge confidential information or secrets