Adjectives are often used without nouns.
To refer to some well-known groups of people
The structure the + adjective is used to talk about some well-known groups of people. Examples are: the blind, the deaf, the unemployed, the rich, the poor, the young, the old, the dead etc.
He is collecting money for the blind. (= He is collecting money for blind people.)
Blessed are the meek.
The government should do something for the poor.
Note that these expressions are always plural. The blind means all blind people. Similarly, the dead means all dead people. Adjectives are not normally used in this way without the.
Blessed are the meek. (NOT Blessed are meek.)
These expressions cannot be used with a possessive ‘s.
The problems of the blind should be properly addressed. OR Blind people’s problems should be properly addressed. (NOT The blind’s problems should be properly addressed.)
In a few fixed phrases, the + adjective can have a singular meaning. Examples include: the accused, the former, the latter, the deceased etc.
The accused was released on bail.
Note that plural meanings are also possible.
An adjective can be used after the to refer to some abstract quality or idea.
She doesn’t believe in the supernatural.
The future (= futurity) is unknown to us.
Adjectives of nationality
Some adjectives of nationality ending in -sh or -ch can be used after the without nouns. These adjectives include
Irish, Welsh, English, British, Spanish, French etc.
The Irish are proud of their sense of humor.
Note that the expressions the Irish, the English etc., are plural.The singular equivalents are for example an Irishman or an Englishwoman.