Sometimes adjectives no longer want to play the roles assigned to them and become nouns. At least that's what happens in Russian once in a while. Such newborn adjective-nouns look and conjugate like adjectives but play the role of nouns in a sentence. I'll give you a few examples.
книжный - bookstore
Я купила журнал в книжном. - I bought a magazine in a bookstore.
столовая - dining-hall
В столовой было много народу. - There were many people in the dining-hall.
гостиная - living room
В их доме две гостиных. - There are two living rooms in their house.
парикмахерская - hairdressing saloon
Он пошёл в парикмахерскую. - He went to a hairdressing saloon.
слепой - blind person
глухой - deaf person
У слепых и глухих бывает много проблем. - Blind and deaf people face many problems.
немой - mute person
Немые учат язык жестов. - Mute people learn sign language.
русский - Russian person
Русская и американка позавтракали в кафе. - A Russian and an American girl had a breakfast in a cafe.
дорогой - darling, dear
Дорогой, принеси мне мой телефон. - Darling, bring me my phone.
военный - military man
По улице шли военные. - Military men walked down the street.
другой - other
Мы часто не замечаем проблемы других. - We often don't notice problems of others.
остальной - the rest
Остальное можно оставить здесь. - The rest can be left here.
