1. 看不见的;隐形的
    If you describe something as invisible, you mean that it cannot be seen, for example because it is transparent, hidden, or very small.

    e.g. The lines were so finely etched as to be invisible from a distance...
           线条被蚀刻得如此精细，在远处看都看不见。
    e.g. The belt is invisible even under the thinnest garments.
           这种腰带即便在最薄的衣衫下都看不出来。

2. 无形的
    You can use invisible when you are talking about something that cannot be seen but has a definite effect. In this sense, invisible is often used before a noun which refers to something that can usually be seen.

invisible的近义词

    e.g. Parents fear they might overstep these invisible boundaries...
           父母担心他们可能会逾越这些无形的界限。
    e.g. Her father's face had suddenly tightened as though he was being strangled by invisible hands.
           她父亲的脸突然僵硬了,仿佛是被无形的双手扼住了脖子。

3. 被人忽视的;不为人注意的
    If you say that you feel invisible, you are complaining that you are being ignored by other people. If you say that a particular problem or situation is invisible, you are complaining that it is not being considered or dealt with.

    e.g. It was strange, how invisible a clerk could feel...
           一名办事员会感到如此受人忽视，令人觉得不可思议。
    e.g. The problems of the poor are largely invisible.
           穷人的问题大多不受重视。

4. (故事中的人或事物)隐身的，隐形的
    In stories, invisible people or things have a magic quality which makes people unable to see them.

    e.g. ...The Invisible Man.
           《隐形人》

5. (收入)非贸易的,无形的
    In economics, invisible earnings are the money that a country makes as a result of services such as banking and tourism, rather than by producing goods.

    e.g. Tourism is Britain's single biggest invisible export...
           旅游业是英国最大的一项无形输出。
    e.g. The revenue from tourism is the biggest single item in the country's invisible earnings...
           旅游业收入是该国无形收益当中最大的一项。

6. 无形服务业(如银行业、旅游业)
    Invisibles are services such as banking and tourism, which provide a country's invisible earnings.