Usage: AWAY [<message>]
The system will automatically send this message to anyone trying to message you. The message will also show in your information if someone issues the command WHOIS on you. It is often used to tell people that you are away from your computer. If you no longer wish to be seen as away, then simply type /AWAY with no message and the away message will no longer be displayed.
/away I'm walking my dog, be back later.
You can also use it if you are staying active but do not want to reply to private messages. For example, some people will set their away message to something like "Please talk to me in the channel, I am busy and not replying to private messages.".
Additionally, private messages can be blocked entirely, see CMODE +m.