knocker vs depreciator

knocker and depreciator both are nouns.

Word	Noun	Adjective	Verb	Adverb
knocker	Yes	No	No	No
depreciator	Yes	No	No	No

As nouns, knocker and depreciator are synonyms defined as:

knocker and depreciator: one who disparages or belittles the worth of something

Other synonyms of knocker include detractor, disparager.

knocker (noun)	depreciator (noun)
a device (usually metal and ornamental) attached by a hinge to a door	one who disparages or belittles the worth of something
either of two soft fleshy milk-secreting glandular organs on the chest of a woman
one who disparages or belittles the worth of something
a person who knocks (as seeking to gain admittance)
(Yiddish) a big shot who knows it and acts that way; a boastful immoderate person