Possibly from צבֿועק(tsvuak, “hypocrite”) + ־ען(-en), with the shift to ־טש־(-tsh-) being a result of the Slavic first palatalization, or being derived from the feminine form צבֿועטשקע(tsvuatshke).
Justus van de Kamp et al., “צבֿועטשען” in Jiddisch-Nederlands Woordenboek [Yiddish-Dutch Dictionary], Amsterdam: Stichting Jiddische Lexicografie, 1987-present (ongoing). [1].
Beinfeld, Solon, Bochner, Harry (2013) “צבֿועטשען”, in Comprehensive Yiddish-English Dictionary, Bloomington, Indiana: Indiana University Press, →ISBN