The Collaborative International Dictionary
Schnorrer \Schnor"rer\, n. [Yiddish, fr. G. schnurrer, fr. schnurren to hum, whir, hence, from the sound of the musical instrument used by strolling beggars, to beg.] Among the Jews, a beggar.
Douglas Harper's Etymology Dictionary
1892, from Yiddish, "beggar," from German slang schnurrer, from schnurren "to go begging" (slang), perhaps ultimately imitative of the sound of pleading or whining (compare sneer, snorkel, snarl).
Wiktionary
n. sponger (person who takes advantage of the generosity of others)
Wikipedia
Schnorrer (שנאָרער; also spelled shnorrer) is a Yiddish term meaning " beggar" or "sponger". The word Schnorrer also occurs in German to describe a freeloader who frequently asks for little things, like cigarettes or little sums of money, without offering a return. The English usage of the word denotes a sly chiseler who will get money out of his acquaintances any way he can, often through an air of entitlement. A schnorrer is distinguished from an ordinary beggar by dint of his boundless chutzpah. Like "moocher", "schnorrer" does not apply to direct begging or destitution, but rather a habit of getting things (food, tools) by politely or insistently borrowing them with no intention of return.
The term, which is used in a pejorative or ironic sense, can also be used as a backhanded compliment to someone's perseverance, cleverness, or thrift. For instance, Azriel Hildesheimer, known for his travels around Europe to spread his rabbinical wisdom to the poor, and for his refusal to accept payment for his services, was sometimes referred to as the "international schnorrer" for his reliance on the local community to house and feed him wherever he went. Alternatively, Theodor Herzl described his early Eastern European immigrant supporters among the Ostjuden, as his "army of schnorrers". Israel Zangwill later described a schnorrer as a beggar who would chide a donor for not giving enough. The Schnorrer Club of Morrisania was a German-American social club in the Bronx, New York.
Schnorrers sometimes begged for the dowries of poor women (Hakhnasat Kallah); a practice which was allowed even when it disrupted the public study of the Torah.
Additionally, the word is the origin of the modern Hebrew verb לשנורר (leshnorer), which can be roughly defined as "getting small things without offering return."
Usage examples of "schnorrer".
He did, after all, run the hab. But why did he have to bring a schnorrer like Mud along?