1. 未经区分的：undistinguishably 难辨别地 | undistinguished 未经区分的 | undistorted 未失真的

2. 未觉察的：undistinguishableundistinguishably 难辨 | undistinguished 未觉察的 | undistorted 无失真的

1. 不出色的；平凡的；平庸的
    If you describe someone or something as undistinguished, you mean they are not attractive, interesting, or successful.

    e.g. ...his short and undistinguished career as an art student.
           他短暂而平庸的艺术专业学习生涯
    e.g. ...this rather undistinguished, grimy industrial town.
           这座毫无特色、尘灰飞扬的工业城镇

1. not worthy of notice

    Synonym: insignificant