A hapax whose alternative interpretation is ‘one having defective eyebrow’; though in most Hebrew dictionaries this word is interpreted as ‘humpbacked’, the context of Lv 21: 20 rather suggests a defect in the eye area.
Hebrew
gibbēn - one having defective eyebrow (?)
(HALOT 174)
The context of Lv 21: 20 rather points to this meaning (cf. [Ja. 207]); usually
understood as ‘hump-backed’.