purplish-red vs purple-red

purplish-red is a noun but purple-red is not a noun.

Word	Noun	Adjective	Verb	Adverb
purplish-red	Yes	Yes	No	No
purple-red	No	Yes	No	No

As adjectives, purplish-red and purple-red are synonyms defined as:

purplish-red (noun)	purple-red (noun)
a red with a tinge of purple

purplish-red (adjective)	purple-red (adjective)
of red tinged with purple	of red tinged with purple