From an unused root (meaning to flit); a fly (especially one of a stinging nature) -- fly.
Englishman's Concordance
1) fly Part of Speech: noun masculine A Related Word by BDB/Strong’s Number: from an unused root (meaning to flit) Same Word by TWOT Number: 523a
Brown-Driver-Briggs
זְבוּבnoun masculineEcclesiastes 10:1fly (as moving to and fro in the air? compare Fl NHWBi. 438 b; Late Hebrew id., Assyrian zumbu, DlS 63 f.; Arabic , Aramaic דִּיבָבָא, , ); — literal only זְבוּבֵי מָוֶתEcclesiastes 10:1 i.e. dead flies; so AV RV Hi Now and others; > ᵐ5 De and others death-bringing, deadly flies; זְבוּב metaphor of Egyptian army Isaiah 7:18 ("" דְּבוֺרָה, bee, of Assyrian); on בַּעַלזְבוּב see בַּעַל II. 4, p. 127 above
Ecclesiastes 10:1 HEB: זְב֣וּבֵי מָ֔וֶת יַבְאִ֥ישׁ NAS: Dead flies make a perfumer's oil KJV: Dead flies cause the ointment INT:flies Dead stink
Isaiah 7:18 HEB:יִשְׁרֹ֤ק יְהוָה֙ לַזְּב֔וּב אֲשֶׁ֥ר בִּקְצֵ֖ה NAS: will whistle for the fly that is in the remotest part KJV: shall hiss for the fly that [is] in the uttermost part INT: will whistle the LORD the fly is in remotest