"Dai gui" is a Cantonese slang term that is commonly used to describe someone who is powerful or influential. There are many synonyms for this term, including "big shot", "mogul", "tycoon", "heavyweight", "baron", "magnate", "eminent", "notable" and "dignitary". All of these terms imply someone who has a high degree of power, authority or influence, whether it be in business, politics, or another area. However, each synonym may have a slightly different connotation or emphasis, depending on the context in which it is used. Regardless, all of these terms convey the idea of someone who is not to be underestimated.