Lexical Definition

‎נָסַס‎ nâçaç (naw-sas') to faint ^H:V
a primitive root

faint.

• to wane, i.e. be sick

1) (Qal) to be sick

Brown-Driver-Briggs

I. [‎נָסַס‎] verb be sick (?; compare Syriac id., and especially debilis, infirmus, aegrotans, etc., PS²³⁸⁷; ᵑ7 ‎נְסַס‎ be sad; Assyrian nasâsu, wail, lament Dl^{HWB 472}; Arabic is go at a gentle pace); — only Qal Participle active (si vera lectio) ‎כִּמְסֹס נֹסֵס‎ Isa 10:18 like the wasting away of a sick man (so Thes Ew De Che Di Du).

Brown-Driver-Briggs References