as a bash alias:

  word_pass() {
      cat /usr/share/dict/words | awk 'BEGIN{srand();}{print rand()"\t"$0}' | sort -k1 -n | cut -f2 | head -n 4 | tr "\\n" " " && echo 
  }

then:

  $ word_pass
  corticifugally tetraploidy democrat vibrionic

(if you notice how this works, you can see that it isn't super-efficient, but it works)