Akkadian

gubbuḫu - bald (CAD A 117, AHw. 295)

Var. ḳubbuḫu.

PS
*gbḫ - to be bald (on the forehead) (SED I No. 15v)
Semantically and phonetically very likely contaminated with gVbh(­at)­ ‘forehead, front’ (see SED I No. 68).