red-orange vs reddish-orange

red-orange and reddish-orange both are adjectives.

Word	Noun	Adjective	Verb	Adverb
red-orange	No	Yes	No	No
reddish-orange	No	Yes	No	No

As adjectives, red-orange and reddish-orange are synonyms defined as:

Other synonyms of red-orange include flame-orange.

red-orange (adjective)	reddish-orange (adjective)
of orange tinged with red	of orange tinged with red