lilac vs lilac-colored

lilac is a noun but lilac-colored is not a noun.

Word	Noun	Adjective	Verb	Adverb
lilac	Yes	Yes	No	No
lilac-colored	No	Yes	No	No

As adjectives, lilac and lilac-colored are synonyms defined as:

Other synonyms of lilac include lavender.

lilac (noun)	lilac-colored (noun)
any of various plants of the genus Syringa having large panicles of usually fragrant flowers

lilac (adjective)	lilac-colored (adjective)
of a pale purple color	of a pale purple color