sickish vs nauseous

sickish and nauseous both are adjectives.

Word	Noun	Adjective	Verb	Adverb
sickish	No	Yes	No	No
nauseous	No	Yes	No	No

As adjectives, sickish and nauseous are synonyms defined as:

Other synonyms of sickish include nauseated, queasy, sick.

sickish (adjective)	nauseous (adjective)
feeling nausea; feeling about to vomit	feeling nausea; feeling about to vomit
	causing or able to cause nausea