role vs lieu

role and lieu both are nouns.

Word	Noun	Adjective	Verb	Adverb
role	Yes	No	No	No
lieu	Yes	No	No	No

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

role: the actions and activities assigned to or required or expected of a person or group
lieu: the post or function properly or customarily occupied or served by another

Other hyponyms of role include capacity, hat, portfolio, place, position, stead, second fiddle.

role (noun)	lieu (noun)
the actions and activities assigned to or required or expected of a person or group	the post or function properly or customarily occupied or served by another
normal or customary activity of a person in a particular social setting
what something is used for
an actor's portrayal of someone in a play