mulleus

Latin

Uncertain;^[1] proposed derivations include:

From mullus (“mullet”), but considered folk etymology
From Proto-Indo-European *melh₂-. Cognates include Ancient Greek μέλας (mélas, “black”), Sanskrit मल (mala, “dirt, filth, dust”), Latvian melns, and Old Prussian melne. Driessen rejects the connection with adj. in **-no- meaning 'black' since Proto-Italic *melnos / *mlnos would not yield Lat. mullus but melnus / blanus, cf. blandus (“soft”)
From Proto-Italic *molweyos, from *ml-uo (“dark, red, dirty”) IE cognates Latvian mul̃vas "reddish, yellowish," itself from *melh₂-.

mulleus (feminine mullea, neuter mulleum); first/second-declension adjective

Case / Gender	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Number	Singular			Plural
Nominative	mulleus	mullea	mulleum	mulleī	mulleae	mullea
Genitive	mulleī	mulleae	mulleī	mulleōrum	mulleārum	mulleōrum
Dative	mulleō	mulleae	mulleō	mulleīs
Accusative	mulleum	mulleam	mulleum	mulleōs	mulleās	mullea
Ablative	mulleō	mulleā	mulleō	mulleīs
Vocative	mullee	mullea	mulleum	mulleī	mulleae	mullea

Colors in Latin · colōrēs (layout · text)
albus, candidus, subalbus, niveus, cēreus, marmoreus, eburneus, cānus, blancus (ML.)	glaucus, rāvus, pullus, cinereus, cinerāceus, plumbeus, grīseus (ML. or NL.)	niger, āter, piceus, furvus
ruber, rūbidus, rūfus, rubicundus, russus, rubrīcus, pūniceus, murrinus, mulleus; cocceus, coccīnus, badius	rutilus, armeniacus, aurantius, aurantiacus; fuscus, suffuscus, colōrius, cervīnus, spādīx, castaneus, aquilus, fulvus, brunneus (ML.)	flāvus, sufflāvus, flāvidus, fulvus, lūteus, gilvus, helvus, croceus, pallidus, blondinus (ML.)
galbus, galbinus, lūridus	viridis	prasinus
cȳaneus	caeruleus, azurīnus (ML.), caesius, blāvus (LL.)	glaucus; līvidus; venetus
violāceus, ianthinus, balaustīnus (NL.)	ostrīnus, amethystīnus	purpureus, ātropurpureus, roseus, rosāceus

^ Walde, Alois, Hofmann, Johann Baptist (1954) “mulleus”, in Lateinisches etymologisches Wörterbuch (in German), 3rd edition, volume 2, Heidelberg: Carl Winter, page 122