Meaning

noun (Yiddish) a big shot who knows it and acts that way; a boastful immoderate person

noun a person who knocks (as seeking to gain admittance)

noun one who disparages or belittles the worth of something

originEtymology tree English knock Proto-Indo-European *-yósder. Proto-Italic *-āzijos Latin -āriusnom. Latin -āriusbor. Proto-Germanic *-ārijaz Proto-West Germanic *-ārī Old English -ere Middle English -ere English -er English knocker From knock + -er.

Etymology from Wiktionary, CC BY-SA 3.0