let vs prevent

let is a noun but prevent is not a noun.

Word	Noun	Adjective	Verb	Adverb
let	Yes	No	Yes	No
prevent	No	No	Yes	No

let (noun)	prevent (noun)
a serve that strikes the net before falling into the receiver's court; the ball must be served again

let (verb)	prevent (verb)
leave unchanged	stop (someone or something) from doing something or being in a certain state
cause to move; cause to be in a certain position or condition	keep from happening or arising; make impossible
actively cause something to happen
consent to, give permission; permit
grant use or occupation of under a term of contract
make it possible through a specific action or lack of action for something to happen