spill the beans vs let on

spill the beans and let on both are verbs.

Word	Noun	Adjective	Verb	Adverb
spill the beans	No	No	Yes	No
let on	No	No	Yes	No

As verbs, let on is a hypernym of spill the beans; that is, let on is a word with a broader meaning than spill the beans:

spill the beans: divulge confidential information or secrets
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

Other hypernyms of spill the beans include break, bring out, disclose, discover, divulge, expose, give away, let out, reveal, uncover, unwrap.

spill the beans (verb)	let on (verb)
divulge confidential information or secrets	make known to the public information that was previously known only to a few people or that was meant to be kept a secret