yodan verb with 'mu' ending (archaic), intransitive verb
turn red; become reddish; become discolored
Archaic intransitive verb. In modern Japanese, 赤くなる or 赤らむ are used instead. The gloss 'rufous' is a technical color term; 'reddish-brown' may be more accessible.
In classical Japanese, leaves turning red was expressed as あかむ.
nidan verb (lower class) with 'mu' ending (archaic), transitive verb
Archaic transitive verb. The modern equivalent is 赤める. The cross-reference to 赤める supports this relationship.
See also: 赤める
赤む was also used as a transitive verb, but nowadays 赤める is common.
Archaic verb; the kanji spelling is the only written form given.
Derived from 赤 (aka, 'red') + verbal suffix む (mu). The exact historical development is uncertain, but it follows a pattern seen in other color-change verbs.