Reconstructions

Proto-MSA
*ṯ̣br - to nag, to offend (Kogan 2015:575)
The origin of Proto-MSA *ṯ̣br ‘to nag, to offend’ is unknown. (Kogan 2015:575)
Proto-MSA
*ṯ̣a(h)r - on, over (Kogan 2015:575)

The original anatomical meaning is completely lost throughout this group. Semantically similar prepositional use of reflexes of *ṯ̣a(h)r- is admittedly attested in a few other Semitic languages (SED I No. 284). (Kogan 2015:575)

Proto-MSA
*ṯ̣aḥam - urine (Kogan 2015:67)
Proto-MSA
*ṯ̣arb- - piece of wood (Kogan 2015:575)

The origin is unknown. It would be tempting to identify it with Gez. ṣaraba ‘to hew,’ ṣarb ‘plank,’ ṣərrāb ‘splinter, shaving’ and its cognates throughout EthS (CDG 563), but this comparison is difficult in view of reliable parallels with ṣ elsewhere in Semitic (notably, in Soq. ṣérob ‘couper,’ LS 357). (Kogan 2015:575)

Proto-MSA
*ṯ̣wy - to smell (Kogan 2015:575–576)
Possible cognates of Proto-MSA *ṯ̣wy ‘to smelľ are extensively discussed in SED I No. 286. From the semantic point of view, the closest parallels are Ugr. ṯ̣ˀu ‘exhalation, secretion’ (DUL 1007) and Gez. ṣiˀ ‘bad smell.’ Also remarkable are Hbr. ṣōˀā, ṣēˀā ‘excrement,’ ṣē(ˀ) ‘filth’ (HALOT 992) and Gez. ṣiˀat ‘rot, filth, stench, excrement’ (CDG 567). (Kogan 2015:575-576)
Proto-MSA
*ṭlf - to skim off (Kogan 2015:574)

The origin is uncertain, although an ultimate connection with PES *ṭlf ‘to snatch, to abduct’ is not unlikely. (Kogan 2015:574)

Proto-MSA
*wḳf - to be silent (Kogan 2015:576)
As argued by M. Bittner (1911:81) and W. Leslau, Proto-MSA *wḳf ‘to be silent’ is likely related to Arb. wqf ‘to become still, to stop, to stand’. See further DRS 609. Any connection with Akk. ḳâpu ‘to buckle, to collapse’? (Kogan 2015:576)
Proto-MSA
*wṣl - to help (SEDonline)
Proto-MSA
*wṭb - to beat, to tan (JL 294)
Proto-MSA
*wzm - to give; to lend (Kogan 2015:576)
“Must be related to Arab. wzm ‘to pay a debt; to join a small piece of something to what is similar to it” (LA 12 756), so sparsely attested that one may wonder whether it is autochtonous in Arabic. A borrowing from Arabic into MSA is, in this case, quite unlikely” (Kogan 2015:576)