Here are some examples:
* Teacher: A person who teaches.
* Writer: A person who writes.
* Singer: A person who sings.
* Baker: A person who bakes.
While -er is the most common suffix for "a person who", there are other suffixes that can also be used. Some examples include:
* -ist: This suffix is often used for people who follow a particular belief or practice, like an artist, a scientist, or a socialist.
* -ian: This suffix is used for people who are from a particular place or belong to a particular group, like a musician, a librarian, or a historian.
* -or: This suffix is sometimes used to indicate a person who does something, like an actor, a conductor, or a governor.
It's important to note that not all words ending in these suffixes necessarily mean "a person who". For example, "baker" clearly means "a person who bakes", but "water" doesn't mean "a person who waters."