patient vs arthritic

patient and arthritic both are nouns.

Word	Noun	Adjective	Verb	Adverb
patient	Yes	Yes	No	No
arthritic	Yes	Yes	No	No

As nouns, arthritic is a hyponym of patient; that is, arthritic is a word with a more specific, narrower meaning than patient:

patient (noun)	arthritic (noun)
the semantic role of an entity that is not the agent but is directly involved in or affected by the happening denoted by the verb in the clause	a person afflicted with arthritis
a person who requires medical care

patient (adjective)	arthritic (adjective)
enduring trying circumstances with even temper or characterized by such endurance	of or pertaining to arthritis