Cons:

• Only use of two words
• Doesn\'t check if you are an op
• Cannot add more words
• Some scripting mishaps

Here is the updated code (with a \'mini-tutorial\' on what I changed):

on @*:TEXT:*:#:{ 
  ; the above line is not much different from your first, the @ checks if you are an op in the channel
  var %swear fuck,bitch
  ; swear words that are checked are in this local variable (can be added or removed)
  if ($istok($1-,%swear,32)) { 
   ; checks if any of the words are in the text
   ban -k # $nick Swearing is prohibited. 
   ; ban/kick\'s the nick w/ above msg
  }
}

Try that w/o the ; comments. They were just used to help you understand. And if you already knew about what I\'m talking about, then just ignore them.