patient vs outpatient

patient and outpatient both are nouns.

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

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

patient: a person who requires medical care
outpatient: a patient who does not reside in the hospital where he is being treated

patient (noun)	outpatient (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 patient who does not reside in the hospital where he is being treated
a person who requires medical care

patient (adjective)	outpatient (adjective)
enduring trying circumstances with even temper or characterized by such endurance