The origin is uncertain, but Leslau may be correct to relate it to PS *hlk ‘to go.’ (Kogan 2015:573)
With no evident Semitic etymology (for the rather sparse Akkadian comparanda see Kogan 2015:539).
The origin is unknown (Kogan 2015:574)
Is likely related to Tgr. šəfər ‘manure, dung’ (WTS 230), but further possible cognates are rather uncertain (SED I No. 282). (Kogan 2015:575)
In a personal communication, M. Krebernik suggests an interesting possibility of comparing proto-MSA *ṯḥr ‘to wound’ with Sargonic Akkadian šaˀāru (iš₁₁-ar) ‘to conquer, to win, to destroy’ (CAD Š₁ 2). This etymology provides a far better balance of semantic and phonological/orthographic features than the more traditional comparisons with either PS *ṯγr ‘to break’ or Arabic ṯˀr ‘to take blood-revenge.’ (Kogan 2015:575, fn. 1493)
Deictic adverbs involving the element *ṭ (DRS 527) have no parallel elsewhere in Semitic.
Is related to Akk. ṭēru ‘mud, silt’, but no further cognates elsewhere in Semitic could be detected. (Kogan 2015:573)