Origin: Latin suffix -ous
Religious has 7 different meanings across 2 categories:
a member of a religious order who is bound by vows of poverty and chastity and obedience
"The monk took his final vows as a religious, pledging to live in solitude within the monastery."
A member of a religious order, i.e. a monk or nun.
"The local convent welcomed three new nuns who had recently taken their vows as religious."
In plain English: A religious person is someone who believes in and follows a specific faith or spiritual system.
"His religious beliefs guided his daily actions."
Usage: Use this noun form specifically to refer to members of monastic orders like monks and nuns who have taken vows. It is distinct from the adjective describing faith-based beliefs or practices in general life.
having or showing belief in and reverence for a deity
"a religious man"
"religious attitude"
of or relating to clergy bound by monastic vows
"the religious or regular clergy conducts the service"
Concerning religion.
"The museum opened its new exhibit on religious artifacts from ancient civilizations."
In plain English: Religious describes someone who believes in and follows a specific god or group of gods.
"She is religious and goes to church every Sunday."
The word "religious" entered English via Middle English and Old French, ultimately tracing back to the Latin religiōnus, which originally meant "conscientious." It shares a root with the noun "religion," carrying forward its core sense of being devoted to spiritual duties.