Actually, this one is more efficient I think.

Code:
on *:START:{
  window @Word-Matches
}


on *:TEXT:*:#: {
  var %wordlist = word1,word2,word3,word4
  var %cnt = 1
  while (%cnt <= $numtok(%wordlist,44)) {
    if ($gettok(%wordlist,%cnt,44) isin $strip($1-)) {
      echo -te @Word-Matches Word found: $gettok(%wordlist,%cnt,44)
    }
    inc %cnt
  }
}