on @*:text:*:#:swear $1-
on @*:action:*:#:swear $1-
on @*:notice:*:#:swear $1-
alias -l swear {
  var %s = /\b(niggers|(mother)?fuc?k(er)?|pussy|word|word|word|word|word|word|$&
    $+ vagina|word|word|word|word|word|word|word|word|word|word|word|word|$&
    $+ word|word|word|word|word|word|word|word|word|word|word|word|word)\b/iS
  if (($nick !isop #) && ($regex($1-,%s))) { 
    kick # $nick Please don't use that kind of language here. (Auto-response to word: $regml(1) $+ )
  }
}

That'll match motherf-word, f-word and f-word-er. And you can use the link break to divide the regex match if it gets too long.