a Jew from Lithuania or a neighboring country or region.
Origin of Litvak
1890–95; < Yiddish litvak < Polish litwak Lithuanian person (now obsolete in this sense), derivative of Litwa Lithuania
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
"Jew from Lithuania," 1892, from Polish Litwak "Lithuanian Jew," originally simply "man from Lithuania."
Online Etymology Dictionary, © 2010 Douglas Harper