Proto-Lezghian: *c̣ʷep:V-
Meaning: 1 hard 2 thick (of a flat object)
Agul: c̣up:e-f
Tsakhur: c̣oba-n
Comment: Cf. also Bursh. c̣ube-r, Burk. c̣up:e-f, Fit. c̣ep:i-t / c̣ebbi-t (the latter form showing that the stem actually consists of the root c̣eb- + suffixed -b-).