Humungous is a word that describes something as being extremely large or enormous. There are many synonyms for this word that can be used to convey the same sense of size and magnitude. Some great substitutes for the word humungous are colossal, gigantic, mammoth, massive, and immense. All these synonyms have a similar meaning to humungous, and using them helps to add variety to your writing and keep it from becoming repetitive. Other synonyms for humungous can include jumbo, monster, stupendous, and whopping, among others. Whether you use any of these synonyms or humungous, the key is to use them appropriately, depending on the context of your writing.