DJBA lists an absolute form as זוט, but inasmuch as this appears to be an elided form from zwṭr and no such form is attested in the sources, we have chosen to assume that זוטא is in fact the absolute form as well. (Cf. BQ 55a where זוטא is paralleled by אריך, while at MidGad San 9(b) the absolute is זיט!
One suspects that the Syriac example in Bar Bahlul, otherwise unknown in actual texts and isolated in mss. of that work, is idiolectic.