Reflexive pronouns are words that refer back to the subject of a sentence. They are formed by adding "-self" or "-selves" to certain pronouns. Common reflexive pronouns include myself, yourself, himself, herself, itself, ourselves, and themselves. They are used when the subject and the object of the verb are the same. For example, in the sentence "She taught herself to play the piano," the reflexive pronoun herself indicates that she is both the teacher and the learner. Reflexive pronouns can also emphasize the subject, as in "I did it myself," highlighting the individual's role in the action.