kawaisou 可哀想

In Japanese, kawaisou 可哀想 means "oh, that poor thing!" It's a phrase used when you feel pity for something.

More literally, kawaisou 可哀想 is an ateji for kawaisou 可愛そう, which means "it seems pitiable." And that kawaisou comes from the i-adjective kawaii 可愛い, which means "cute," but can also mean "pitiable," combined with the suffix -sou ～そう, which means "it seems."

The way it's used, though, is really to express pity or sympathy for someone or something, specially right before going help them. For example:

• kawaisou da
  可哀想だ
  [It] seems pitiable.
• kare ga kawaisou da
  彼が可哀想だ
  He seems pitiable.
  He seems [miserable.]
  [I feel sorry for him.]
• kawaisou dakara tasukeyou
  可哀想だから助けよう
  Let's help [him] because [he seems miserable].
• hitori bocchi de kawaisou
  一人ぼっちで可哀想
  [He] seems [miserable] by being alone.
  [I feel bad for him, because he's all by himself.].