Definition of humongous. : extremely large : huge a humongous building humongous amounts of money.Click to see full answer. In this regard, is humongous a proper word?Humongous is an American slang word coined in the 1970’s, copying more proper words like tremendous or enormous. If you want to describe something that’s so big it’s hard to really measure, like the national debt or the number of cells in your body, you can use the world humongous. Just don’t use it in a formal paper. is humongous a word in the English dictionary? Meaning of humongous in English. very large: We had our picture taken in New Mexico before a humongous cactus. Improve your vocabulary with English Vocabulary in Use from Cambridge. Herein, what is another word for humongous? (also astronomic), Brobdingnagian, bumper, colossal, cosmic.When did humongous become a word?The Oxford English Dictionary introduced the term in 1989 but still marks it as “slang.” Merriam-Webster’s, however, counts it as “real.” In 2007, the dictionary admitted ginormous into its pages. M-W noted its etymology as a combination of gigantic and enormous.