* Colossal: This is a very common synonym that emphasizes vastness and immensity.
* Enormous: This word emphasizes size and scale, making it a good synonym for gargantuan.
* Gigantic: This word implies a great size, often exceeding normal proportions.
* Immense: This word emphasizes the vastness and extent of something, making it a suitable synonym for gargantuan.
* Massive: This word emphasizes weight and bulk, highlighting the sheer size and density of something.
* Monumental: This word implies something that is very large and impressive, making it a suitable synonym for gargantuan in some contexts.
The best synonym for "gargantuan" depends on the specific context and the nuance you want to convey.