PWS

*ḥwr - to be black on white or white on black (Kogan 2005c:191)

PArm
*ḥwr - to be white (Kogan 2011: 198)
Proto-MSA
*ḥā̆wVr - black (Kogan 2015: 541)

According to Bulakh 2004:273-274, the term for “black” in Soqotri, as well as in other MSA, can be related to Arb. ḥawar- ‘intense whiteness of white of the eye and intense blackness of the black thereof’, in its turn connected with Common Aramaic *ḥwr ‘to be white’. (Kogan 2015: 541)

Arabic
ḥwr - II. to whiten (Lane 665)
Arabic
ḥawar- - intense whiteness of the white of the eye and intense blackness of the black thereof (Lane 666)
Arabic
ˀaḥwar- - one who has eyes of pure white and black (Lane 666)