Answer:
Many
Step-by-step explanation:
An indefinite pronoun is a pronoun (which is a substitution for a noun) that refers to one or more objects, beings, places, ideas, etc. that are not specified.
The word "many," then, is an indefinite pronoun because it is not specific, it does not indicate who "many" are.
Other examples of indefinite pronouns are several, another, anything, any, anybody, anyone, either, neither, nobody, no, none, someone, some, each, everybody, few, and all.