The hiragana ends with an う sound, so you know this is a verb. The kanji itself means return, and this verb is transitive, meaning it takes a direct object. You send someone back. You send them home. And tell them to never come near you again. So this means to send someone back or to send someone home.

In fact, most verbs ending in す are transitive. To help you remember that, think of suing (す) someone to make sure they go home!