Definition:
An indefinite pronoun is “a pronoun that does not refer to any person or thing in particular, for example ‘anything’ and ‘everyone”
"indefinite pronoun." Oxford Learner's Dictionaries, 2022, www.oxfordlearnersdictionaries.com/us/definition/english/indefinite-pronoun. Accessed 29 Aug. 2022.
Informal Definition:
Vague or undefined antecedent is a pronoun that doesn’t have a definite subject or thing that it is referencing. An undefined antecedent can also be referred to as an indefinite antecedent. These pronouns referenced in the definition are being used as an antecedent.
"Indefinite Pronouns." GrammerBook.com, 25 Aug. 2022, www.grammarbook.com/blog/pronouns/indefinite-pronouns/. Accessed 29 Aug. 2022.
Example:
Definite: She drives the car. (The pronoun reference is specific to a person.)
Indefinite: Anyone can drive the car. (The pronoun reference is general; no particular person is identified.)
Etymology:
late 14c. in grammar ("noun to which a pronoun refers") and in logic ("if A is, then B is;" A is the antecedent, B the consequent), from Old French antecedent (14c.) or directly from Latin antecedentem (nominative antecedens), noun use of present participle of antecedere "go before, precede," from ante "before" (from PIE root *ant- "front, forehead," with derivatives meaning "in front of, before") + cedere "to yield" (from PIE root *ked- "to go, yield").
"Antecedent (n.)." Online Etymology Dictionary, 26 Feb. 2019, www.etymonline.com/word/antecedent. Accessed 29 Aug. 2022.