spring vs let on

spring is a noun but let on is not a noun.

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

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

spring: produce or disclose suddenly or unexpectedly
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 spring include break, bring out, disclose, discover, divulge, expose, give away, let out, reveal, uncover, unwrap.

spring (noun)	let on (noun)
a light, self-propelled movement upwards or forwards
a metal elastic device that returns to its shape or position when pushed or pulled or pressed
the elasticity of something that can be stretched and returns to its original length
a point at which water issues forth
a natural flow of ground water
the season of growth; spring; the beginning of spring

spring (verb)	let on (verb)
develop suddenly	make known to the public information that was previously known only to a few people or that was meant to be kept a secret
produce or disclose suddenly or unexpectedly
spring back; spring away from an impact
move forward by leaps and bounds
develop into a distinctive entity