שִׁיבּוּשׁ, (שָׁבֵשׁ, v. שְׁבִשְׁתָּא) confusion, blunder. R. Hash. 30ᵇ כדי שיהא … שלא בש׳ so that there be time enough to offer … and to sing the appropriate psalm without confusion. Ib. כיון דלא אמור כלל אין לך ש׳ וכ׳ since they recited no song at all (on account of the late hour), there could be no greater confusion than this.