let in vs permit

let in is not a noun while permit is a noun.

Word	Noun	Adjective	Verb	Adverb
let in	No	No	Yes	No
permit	Yes	No	Yes	No

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

let in: allow participation in or the right to be part of; permit to exercise the rights, functions, and responsibilities of
permit: consent to, give permission; permit

Other hypernyms of let in include allow, countenance, let.

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

Other hypernyms of let in include allow, countenance, let.

let in (noun)	permit (noun)
	the act of giving a formal (usually written) authorization
	large game fish; found in waters of the West Indies
	a legal document giving official permission to do something

let in (verb)	permit (verb)
allow participation in or the right to be part of; permit to exercise the rights, functions, and responsibilities of	consent to, give permission; permit
allow to enter; grant entry to	allow the presence of or allow (an activity) without opposing or prohibiting
	make it possible through a specific action or lack of action for something to happen