kick *|<channel> <nickname> [<reason for kick>]

This command revokes the membership of another irc user from a channel in which you are a channel operator. Customarily, it is used to remove troublemakers, flooders, or others who are making a nuisance of themselves. You may specify a reason for the kick, and doing so is considered good style by most; however it is not required.

Again, you must be a channel's operator in order to remove other members from the channel. On some networks (notably the undernet), some users (users with user mode +k turned on, such as the channel service) may not be removed with the KICK command.

From a purely technical point of view, any channel operator may remove any channel member (including themselves) at any time for any reason whatsoever. Notwithstanding this, some channels may have structure and rules governing the discretionary use of the KICK command by its operators. Failure to obey these rules would constitute a breach of trust and you may find your friends no longer op you when you join. This is, as we say, “tough luck”. You should be old enough that we don't have to tell you that others will treat you in the same way you treat them, and picking fights with others is rude.

To remove foobar from channel #blah:

    /kick #blah foobar Go away!

To remove foobar from your current channel:

    /kick * foobar I said go away!!