A quick glance in a Jastrow dictionary shows that the root for bizbuz is
"bazaz" meaning "to divide spoils, to plunder". Thus:
"Bazbuza"- plunder, spoil, ill-gotten goods, as in "bazbuza" (Shir HaShirim
Raba VII, 7).
"Bizbez"- 1. to divide, distribute. Tosefta Megillah IV (III), 21. Baba
Basra 142a. 2. to give away liberally, to give charity on a large scale.
Kesuvos 50a. Baba Basra 11a. 3. to spend unnecessarily, squander.
Bereishis Rabba s. 80
"Bazbez"- 1. to shatter. Esther Rabbah I, 10. 2. to give away, squander.
Targum Koheles III, 22. Kesuvos 67b. Yerushalmi Sotah III, 19a. 3. to
treat lightly, Yerushalmi Terumos XI, 48b. Yerushalmi Shabbos II, 4d.
While I haven't actually looked up any of the sources (Jastrow provides
quotations) it is obvious that the word was very widely used in Talmudic
times. (Jastrow does not indicate every time a word is used in the Talmud
and midrashim. He only provides a selection.) This would place the origin
of the word "bizbus" well before the 16th century (that is actually an
absurd understatement, this would place the word bizbuz before the first
century! Indeed, Jastrow mentions one of the midrashim as discussing the
word une'vuz'be'yu'such"- "and your rewards "(Daniel V, 17) (which, if you
look at the original Hebrew, has the same shoresh as "bizbuz"). This would
mean the word existed in Biblical times!