1. (口头或书面的)警告，警示
    A warning is something which is said or written to tell people of a possible danger, problem, or other unpleasant thing that might happen.

warning的翻译

    e.g. The minister gave a warning that if war broke out, it would be catastrophic...
           部长警告说，战争一旦爆发将会是灾难性的。
    e.g. He was killed because he ignored a warning to put stronger cords on his parachute...
           他忽视了降落伞上要求使用更结实的绳索的警告信息，因而命丧黄泉。

2. 预告;预兆
    A warning is an advance notice of something that will happen, often something unpleasant or dangerous.

    e.g. The soldiers opened fire without warning...
           士兵们在没有发出警告的情况下开了枪。
    e.g. With no warning, he was fired from his job...
           他没有受到任何警告，就被解雇了。

3. 警告的;告诫的
    Warning actions or signs give a warning.

    e.g. She ignored the warning signals...
           她忽视了一些预警信号。
    e.g. Some fog warning signs had been put up with flashing yellow lights.
           一些配有黄色闪光灯的大雾警示标志立了起来。