abyss

abyss
/əˈbɪs; ə`bɪs/ n
hole so deep that it seems to have no bottom 深渊
    (fig 比喻) an abyss of ignorance, despair, loneliness, etc 无知的, 绝望的, 寂寞的...深渊.

牛津英汉双解词典