yellow-orange vs yellowish-orange

yellow-orange and yellowish-orange both are adjectives.

Word	Noun	Adjective	Verb	Adverb
yellow-orange	No	Yes	No	No
yellowish-orange	No	Yes	No	No

As adjectives, yellow-orange and yellowish-orange are synonyms defined as:

yellow-orange (adjective)	yellowish-orange (adjective)
of orange tinged with yellow	of orange tinged with yellow