מְשַׁבֶּשְׁתָּא, (שְׁבַשׁ) a faulty version, a rejected Boraitha, opp. מְתָרַצְתָּא. Gitt. 73ᵃ (ref. to Tosef. ib. VII (V), 2) כיון דקשיא … ומ׳ היא since there is a contradiction between the first and the second clause, it could not have been discussed at college (or an attempt to harmonize would have been recorded), and (therefore) it is to be rejected. Sabb. 121ᵇ; a. fr.