any member of a small class of words found in many languages that are used as replacements or substitutes for nouns and noun phrases, and that have very general reference, as I, you, he, this, who, what. Pronouns are sometimes formally distinguished from nouns, as in English by the existence of special objective forms, as him for he or me for I, and by nonoccurrence with an article or adjective.
But in you guys, it takes on the guise of a pronoun.
Even a campaign to replace the polite pronoun bombed.
In this case, the object pronoun in the idiom entry is someone: give someone a rain check.
Everyone should be careful to use a singular pronoun with singular nouns in their writing.
British Dictionary definitions for pronoun
pronoun
/ˈprəʊˌnaʊn/
noun
1.
one of a class of words that serves to replace a noun phrase that has already been or is about to be mentioned in the sentence or context pron
Word Origin
C16: from Latin prōnōmen, from pro-1 + nōmen noun
Word Origin and History for pronoun
n.
mid-15c., from pro- and noun; modeled on Middle French pronom, from Latin pronomen, from pro- "in place of" + nomen "name, noun" (see name (n.)). A loan-translation of Greek antonymia.
pronoun in Culture
pronoun definition
A word that takes the place of a noun. She, herself, it, and this are examples of pronouns. If we substituted pronouns for the nouns in the sentence “Please give the present to Karen,” it would read “Please give it to her.”