sufferer vs sick person

sufferer and sick person both are nouns.

Word	Noun	Adjective	Verb	Adverb
sufferer	Yes	No	No	No
sick person	Yes	No	No	No

As nouns, sufferer and sick person are synonyms defined as:

Other synonyms of sufferer include diseased person.

sufferer (noun)	sick person (noun)
a person suffering from an illness	a person suffering from an illness
one who suffers for the sake of principle