ailing vs peaked

ailing and peaked both are adjectives.

Word	Noun	Adjective	Verb	Adverb
ailing	No	Yes	No	No
peaked	No	Yes	No	No

As adjectives, ailing and peaked are synonyms defined as:

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

ailing (adjective)	peaked (adjective)
somewhat ill or prone to illness	somewhat ill or prone to illness
	having or rising to a peak