Dolgopolsky2012#1485 reconstructs WSem *
mrḫ ‘to smear’ and suggests that the theme goes back to Nostr *
‘meŕûq˅ ‘to smear’ which, among others, also produced Idg *
smeru‑ ‘ointment’, cf. Grk
mýron ‘unguent, perfume, sweet oil’, Germ *
smerwa‑ ‘fat, grease’ (cf. G
schmieren, denominative of
Schmer, Norw
sm▪r ‘butter, fat’ – Kluge2002).
In contrast, Ehret1989 presents Ar
maraḫ 1
as an “extension” in “iterative” *
ḥ‑ of a reconstructed biconsonantal root *
mr‑ ‘to brush with the fingers’ (cf. ↗
marr‑ /
marar‑). – Other such extensions in Ar, as given by Ehret, are
†mart‑ ‘to smooth’, ↗
maraṯ‑,
†marz‑ ‘to press slightly with the fingertips’,
†mars‑ ‘to macerate and crush with the hand’ (↗
tamarras‑), ↗
maraš‑, ↗
maraʕ‑,
†marġ‑ ‘to anoint with oil’ (cf. also ↗√
mrġ),
†marq‑ ‘to scratch off the wool’ (cf. also ↗√
mrq), and
†mary‑ ‘to stroke the udder of the camel for milking’ (cf. also ↗√
mry).