"Leyser" is the yiddish word for "silent fart".

Though causing a brief irritation, it is soon forgotten.

It is also frequently used to call someone insignificant.
"Sorry, I just dropped a leyser."
"Don't worry too much, the stink will be gone in a second. It was just a leyser."
"That guy thinks he's the shit, but ultimately he's just a leyser."
by kreindel August 5, 2014
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