Reconstructions

Proto-MSA
*rγṣ̂ - to be soft (ML 320; Naumkin et al. 2022:269)
Proto-MSA
*rḥy - to lick (Naumkin et al. 2013a:79)
Proto-MSA
*rḫy - to come loose, to be released (ML 335)
Proto-MSA
*rkt - to step, to tread (Kogan 2015:569)
The origin of Proto-MSA *rkt ‘to step, to tread’ is uncertain, but it may be related to semantically similar roots displaying the biconsonantal element *rk, for which cf. LS 400 under Soq. róked ‘trépigner’ and rékaẓ̂ ‘fouler le sol. (Kogan 2015:569)
Proto-MSA
*rVmrVm- - sea (Kogan 2015:569)
While there is no doubt that the MSA designations of “sea” go back to a single prototype, its exact shape is hard to recover because of deep structural changes in individual languages. Nevertheless, it is tempting to suppose that the Proto-MSA form was close to Eastern Jibbali rέmrɛm, with full reduplication of the biconsonantal element *rVm- (cf. already Bittner 1909:128, 1914:55). The origin of this form is with all probability descriptive (onomatopoetic), but no exact parallel seems to be attested in the Semitic-speaking domain (although, as far as verbal roots are concerned, cf. Akk. ramāmu ‘to rumble, to roar, to howl, to bellow,’ CAD R 116, AHw. 949, Tna. ramram bälä ‘to be an indistinguishable, incomprehensible noise,’ TED 547). (Kogan 2015:569)
Proto-MSA
*sgd - to take away (LS 150)
Proto-MSA
*slb - to wait (Kogan 2015:569)
The origin of Proto-MSA *slb ‘to wait’ is unknown. (Kogan 2015:569)
Proto-MSA
*sar - behind (Kogan 2015:569)
The origin of Proto-MSA *sar ‘behind’ is uncertain. Contra W. Leslau and M. Bittner (1914:15), any connection with PS *ˀaṯar- ‘trace’ can be safely excluded for phonological reasons. Quite far-fetched is the comparison between the MSA terms and Arb. sarīr- ‘the part where the head rests upon the neck’ (Lane 1339), sarāt- ‘back’ (ibid. 1353), Amh. säräsär ‘vertebra, spinal cord’ (AED 487) suggested in SED I No. 253. Shall one rather compare Hbr. swr ‘to turn aside’ (HALOT 748), assuming a semantic development from the more original meaning “to turn back”? (Kogan 2015:569)
Proto-MSA
*šbḥ - to cross, spread legs (Kogan 2015:596)
Proto-MSA
*šaḫar- - old man (Kogan 2015:571)
The origin of Proto-MSA *šaḫar- ‘old man’ is uncertain. Any connection with Akk. šuḫarruru ‘to become dazed, still, numb with fear’ (CAD Š₃ 203), Syr. šḥar ‘timuit’ (LSyr. 771)? One wonders whether Arb. sḫr (II) ‘to constrain, to compel to what one does not desire, to bring into subjection’ (Lane 1324) may also be ultimately related. (Kogan 2015:571)