1) to roll, turn 1a) (Hithpael) to roll, roll up, billow
Full Brown-Driver-Briggs lexicon entry
[אָבַךְ] verb turn (?) (compare Assyrian Abâku Dlw = הָפַךְ; Thes MV and others compare בוך) Hithpa`elוַיִּתְאַבְכוּIsa 9:17roll, roll up, as volume of smoke (of Israel under figure of thickets of forest) see De & compare הִתִהַפֵּךְJudg 7:3.