knocker vs big deal

knocker and big deal both are nouns.

Word	Noun	Adjective	Verb	Adverb
knocker	Yes	No	No	No
big deal	Yes	No	No	No

As nouns, big deal is a hypernym of knocker; that is, big deal is a word with a broader meaning than knocker:

knocker: (Yiddish) a big shot who knows it and acts that way; a boastful immoderate person
big deal: an important influential person

Other hypernyms of knocker include big cheese, big enchilada, big fish, big gun, big shot, big wheel, head honcho.

knocker (noun)	big deal (noun)
a device (usually metal and ornamental) attached by a hinge to a door	anything of great importance or consequence
either of two soft fleshy milk-secreting glandular organs on the chest of a woman	an important influential person
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