Whether you're talking about your gargantuan appetite or a gargantuan building, use the word gargantuan to describe something so big that big just isn't, well, big enough to accurately describe it.
The word gargantuan can refer to an object that's physically massive in size or it can describe something that you perceive, like a feeling or an expectation. For example, you might have a gargantuan misunderstanding with your best friend. The word gargantuan came into English in the 16th century from Gargantua, a character in a series of French novels by the author Francois Rabelais. The books followed the adventures of two giants who were father and son.