Adjectival pronouns are certain limiting adjectives may take the place of nouns. These include:

• this
• that
• these
• those
• each
• all

Qualifying adjectives preceded by an article may stand for a noun in the same way.

For example

the good
the wise
the prudent

However, a noun, in both cases, is properly understood. Hence these adjectival pronouns should be disposed of as adjectives used as nouns.
Pronouns, like nouns, have the characteristic of number; that is, they are either singular or plural. Most pronouns also have different forms to indicate person, gender, and case.