The suffix -er in this context means "someone who performs an action."
The suffix -er, when added to words like teacher, preacher, and dancer, typically means "someone who performs an action." It describes a person who is engaged in or performs a particular activity or action.
The suffix -er is used in different ways depending on the context. In the case of the words teacher, preacher, and dancer, the suffix -er means "someone who performs an action." It is used to indicate that the person is engaging in a particular activity or profession. This suffix can be added to verbs and sometimes nouns to create a noun form of the word that describes the person who carries out the action. So, in this case, teacher refers to someone who teaches, preacher refers to someone who preaches, and dancer refers to someone who dances. Therefore, the correct answer is "someone who performs an action."
