Reconstructions

Proto-MSA
*ṣtt - to watch (Kogan 2015:570)

The origin is uncertain. The same meaning for ṣtt is well attested in the Arabic dialects of Dhofar and Oman (Rhodokanakis 32‒33, Reinhardt 178), but in view of its isolated status within Arabic one may legitimately wonder about the possibility of MSA substratum/adstratum influence. Of some interest may be Arb. ṣitt- ‘what is opposite’ (TA 4 585). Any connection with JPA ṣwt ‘to listen, to give heed’ (DJPA 462), Syr. ṣāt ‘audivit’ (LSyr. 625)? (Kogan 2015:570)

Proto-MSA
*ṣaṭ(a)r- - basket (Kogan 2015:571)

The origin is unknown.

Proto-MSA
*ŝVgVr-at- - ravine (Kogan 2015:572)

The origin is unclear. Of some interest may be Gez. ŝagara ‘to take a step, to amble, to go across’ (CDG 526) and its EthS cognates, note especially Amh. täšaggärä ‘to cross a river, to cross over’ (AED 660).

Proto-MSA
*ŝaḥz- - frankincense (Kogan 2015:572)

The origin is unknown.

Proto-MSA
*ŝVḫāp- - milk (Kogan 2015:572)

There is no fully statisfactory cognate for Proto-MSA *ŝVḫāp- ‘milk.’ Ugr. šḫp ‘colostrum, first milk’ would be directly acceptable both formally and semantically, but the hypothetical attestations of this lexeme in KTU 1.10 iii 25‒26 are highly doubtful. Syr. šḥāpā ‘colostrum’, on which the interpretation of the Ugaritic lexeme obviously depends, is also very sparsely attested and displays š instead of the expected *s, so that its similarity to the MSA forms may be purely accidental. More promising is Arb. šaḫb- ‘milk coming forth from the udder’ in spite of the irregular b. Of further interest can be Amh. šəffəta ‘globules of fat on the surface of milk’, End. šīf ‘clumps of butter coming out of the holes in the pot when the milk is being churned’. Almost certainly unrelated is Akk. šizbu ‘milk’, whose etymology is similarly unknown. (Kogan 2015:572)

Proto-MSA
*ŝry - to skin (Kogan 2015:573)
The origin of Proto-MSA *ŝry ‘to skin’ (or *ŝVry- ‘skin’ if the Soqotri nominal form is primary) is unknown. (Kogan 2015:573)
Proto-MSA
*ŝa(ˀ)p- - trace, foot (SED I No. 269, Kogan 2011: 225)
Proto-MSA
*ṣaγlaf(-at)- - leaf (Kogan 2015:543)

“The origin of Proto-MSA *ṣaγlaf(-at)- ‘leaf’ is uncertain.1418 Leslau’s comparison with Hbr. sāˁīp ‘twig’ (HALOT 762) and Arb. saˁaf- ‘(leaves of) palm branches’ (Lane 1365) is, at the very best, highly tentative”. (Kogan 2015:543)

Proto-MSA
*ṣ̂agm- - cheek (Kogan 2015:573)
One is tempted to follow W. Müller (apud CDG 149) who tentatively connects Proto-MSA *ṣ̂agm- ‘cheek’ with Gez. ṣ̂agama ‘to be on the left hand; to be twisted, distorted’ (CDG 149), Tna. ṣägam ‘left’ (TED 2616), Tgr. ṣäggämä ‘to be difficult’ (WTS 648) as well as Arb. ḍǯm ‘to be crooked, distorted (mouth),’ ḍaǯam- ‘inclining towards one side of the face’ (Lane 1770). (Kogan 2015:573)
Proto-MSA
*ṣ̂γṯ - to hold (Kogan 2015:573)

Also *ṣ̂aγṯ- ‘handfuľ. The origin of Proto-MSA *ṣ̂γṯ ‘to hold’ is unknown. (Kogan 2015:573)