Forewarnings are the signs that something unpleasant or dangerous might happen in the near future. There are many synonyms for this word - harbinger, omen, portent, presage, sign, signal, warning, caution, and premonition. All of these words indicate the importance of early awareness of an upcoming event. A harbinger is a person or something that foreshadows what is to come. An omen is a supernatural sign that predicts a future event. A portent and presage are similar to omens, but they are generally seen as negative predictions. A sign and signal can be seen as general indicators of something to come. A warning is a notice given before something happens to keep people safe. A caution is like a warning, but it emphasizes the need for care and attention. Lastly, a premonition describes a feeling of something impending that is yet to come.