The origin of Proto-EthS *sˁm ‘to kiss’ is unknown. Yemenite Arabic saˁam (Behnstedt 559), correctly identified with the Ethiopian root by W. Müller (apud Leslau), is to be attributed to the contact with an early forerunner of EthS on the Arabian soil.
"The etymology of Proto-EthS *sabˀ is uncertain. One cannot exclude an ultimate connection with Sab. s1bˀ 'to carry out an undertaking, a military campaign', s1bˀt 'expedition, undertaking, journey' (SD 122), Qat. s1bˀ 'to set out, go' (LIQ 157). This comparison would imply an original meaning "gang", "military or working commando." Generalization of the ethnonym s1bˀ 'Saba, Sabaeans' (cf. LLA 359 and Appleyard 1977:8) is also to be seriously considered."
The origin of Proto-EthS *ṣbb ‘to be narrow’ is uncertain. Rather problematic are Leslau’s comparisons with Arb. ḍbb ‘to milk by contracting the hand upon the udder’ (Lane 1761), ḍaff- ‘narrow’ (Lane 1794), pB. Hbr. ṣpp ‘to press’ (Jastrow 1297), Syr. ṣappupā ‘numella (tormenti genus)’ (LSyr. 634).
Borrowed from Cushitic (Appleyard 1977:17).
usually thought to be a Cushitism (but cf. Kogan 2006c: 271 for a tentative comparison with Ugr. ṣṣm ‘salt-works’, Hbr. ṣīṣ ‘salt’)
is derived from *ṭVb ‘breast’
A variant root?