unwell vs sickly

unwell and sickly both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unwell	No	Yes	No	No
sickly	No	Yes	No	No

As adjectives, unwell and sickly are synonyms defined as:

Other synonyms of unwell include ailing, indisposed, peaked, poorly, seedy, under the weather.

unwell (adjective)	sickly (adjective)
somewhat ill or prone to illness	somewhat ill or prone to illness
	unhealthy looking