Until there is a critical text available, an etymology is difficult *(Pre1981 editions read JONEAM, while RLDS editions, based on the original Ms., had JONEUM).
The best derivation, based on the current Book of Mormon edition, is to read a 3m.s. jussive of nʿm, *”to speak oracles” (RFS). See Jeremiah 23:31 for the verbal form.
Based on the former spelling, Joneam, “Jehovah is pleasant,” from the verbal root nʿm, *”to be pleasant,” with prefixed theophoric element for Jehovah. Biblical PNs from
the verbal root include naʿamān, Naaman, *noʿomī, Naomi (JH), and naʿam, Naam, and its feminine counterpart, naʿamah, Naamah (also a place-name) (JAT).
In Luke 3:30, Jonan is reported as a descendant of David in tracing Jesus’ line (JH).
Cf. Egyptian y3nwʿm, EA yanuamma, transliterations of Canaanite place name *yenôʿam (Albright, VESO, pp. 36, 447). The vowels of Jeneum are problematic, however
Cf. NEUM, NEAS?
See also Jeneum / Joneum Variant