Borrowed from Cushitic according to Dolgopolsky, but treated as cognate to the corresponding Cushitic forms in Militarev 2004:309, 2010:65 (cf. SED I No. 160, Appleyard 1977:27).
Derived from the verbal root *wˁl ‘to spend the day,’ for which no persuasive etymology has been suggested so far (cf. CDG 603).
<*ˁVnḳ- with suffixed -r?
May be related to PWS *ˁVṣ̂ā/īṣ̂- '(kind of) bone' (for this meaning shift, cf. Rus. кость meaning both 'bone' and 'playing die').
Clearly borrowed from Cushitic.
The origin of Proto-EthS *bḳʷˁ ‘to be sufficient’ is uncertain, but note Arb. bqˁ = ˀiktafā (TA 20 346).