Gargantuan
Etymology
From Gargantua, the giant hero of François Rabelais’s bawdy sixteenth-century satire "Gargantua and Pantagruel," known for his stupendous size and equally stupendous appetite. His name — itself echoing words for "gullet" — became the adjective for anything of gigantic proportions, still carrying a faint flavor of excess and hunger.
adjective · /gar-GAN-choo-un/
Enormous in size, quantity, or degree.
What it names
Bigness on a colossal, almost comic scale — reach for it when "large" or even "huge" undersells just how vast something is, especially appetites, meals, or undertakings.
Example
Clearing the backlog would be a gargantuan effort, but the team was ready to attempt it.
Related idea
Colossal stresses sheer imposing size; gargantuan keeps a hint of its origin in appetite and excess, fitting things that are vast to the point of gluttony.