An indefinite pronoun is a type of pronoun that does not refer to any specific person, thing, or amount. Instead, it refers to non-specific or unidentified objects, people, or quantities. Indefinite pronouns are used when the speaker or writer wants to refer to something in a general or vague manner.

Examples of indefinite pronouns include:

1. "Someone" - e.g., "Someone left their umbrella here."

2. "Anything" - e.g., "Is there anything I can do to help?"

3. "Everybody" - e.g., "Everybody enjoyed the party."

4. "Nothing" - e.g., "There's nothing in the fridge."

5. "Each" - e.g., "Each of them brought a gift."

6. "Nobody" - e.g., "Nobody knows the answer."

7. "Both" - e.g., "Both of them are coming to the event."

8. "Several" - e.g., "Several students attended the workshop."

Indefinite pronouns are versatile and are used to avoid repetition or to express a lack of specific information. They play an essential role in constructing clear and concise sentences.