1. 二维的;平面的
    A two-dimensional object or figure is flat rather than solid so that only its length and width can be measured.

    e.g. ...new software, which generates both two-dimensional drawings and three-dimensional images.
           可以制作出二维图画与三维图像的新软件

2. (虚构人物形象)无深度的，平面化的,不真实的
    If you describe fictional characters as two-dimensional, you are critical of them because they are very simple and not realistic enough to be taken seriously.

    e.g. I found the characters very two-dimensional, not to say dull.
           我觉得那些人物形象即使不说是乏味无聊，至少也是毫无深度。

1. involving two dimensions

    Synonym: planar

2. lacking the expected range or depth
    not designed to give an illusion or depth

    e.g. a film with two-dimensional characters
           a flat two-dimensional painting

    Synonym: 2-dimensionalflat