Possessive pronouns are words that show ownership or possession. They replace nouns to indicate that something belongs to someone. Common possessive pronouns include my, your, his, her, its, our, and their. For example, instead of saying "the book of John," you can say "his book." These pronouns help avoid repetition in sentences. For instance, instead of saying "This is Sarah's pencil, and that is Sarah's eraser," you can simplify it to "This is Sarah's pencil, and that is hers." Using possessive pronouns makes sentences clearer and more concise.