sitting room vs living-room

sitting room and living-room both are nouns.

Word	Noun	Adjective	Verb	Adverb
sitting room	Yes	No	No	No
living-room	Yes	No	No	No

As nouns, sitting room and living-room are synonyms defined as:

sitting room and living-room: a room in a private house or establishment where people can sit and talk and relax

Other synonyms of sitting room include front room, living room, parlor, parlour.

sitting room (noun)	living-room (noun)
a room in a private house or establishment where people can sit and talk and relax	a room in a private house or establishment where people can sit and talk and relax