How exactly do isin and iswm operate differently? Say, if you wanted to catch an expletive, which would be better?

Code:
on *:text:*:#: {
  if (expletive iswn $1-) { /kick $chan $nick }
  elseif (expletive2 iswm $1-) { /kick $chan $nick }
  etc
}


or

Code:
on *:text:*:#: {
  if (expletive isin $1-) { /kick $chan $nick }
  elseif (expletive2 isin $1-) { /kick $chan $nick }
  etc
}