Byg is a slang word that means large or big. Some synonyms that can be used for byg include humongous, gigantic, mammoth, enormous, colossal, massive, and substantial. All of these words signify something of great size or quantity. For instance, a humongous cake is a cake that's incredibly large in size. A gigantic house is a house that's so big that it's impressive. Mammoth projects are those that require a lot of effort and time to complete, and massive structures are ones that are incredibly huge and imposing. All in all, these synonyms for byg help to paint a picture of something that's larger than life in our minds.