As the word suggests (indefinite = unspecified, unknown, indeterminate, undefined) Indefinite Adjectives give general information about the noun they refer to.
Some common indefinite adjectives are:
Though indefinite pronouns and indefinite adjectives look the same they are used differently in a sentence.
Whilst an indefinite pronoun replaces a noun, an indefinite adjective is placed in front of a noun or pronoun to modify it.
We are meeting some old school friends tonight.
Not many people turned up at the opening of the exhibition.
Do you have any sugar?
The dog barks every time a car passes by!
Indefinite Pronouns in English Grammar – for a comparison with the indefinite adjectives.