immense

Immense means very large in size, amount, or degree. You might describe the ocean as immense, or your homework load, or the slice of cake your brother took, leaving you a tiny sliver.

This word has an immense number of near synonyms: huge, great, enormous, vast, gigantic, colossal, mammoth, copious, tremendous are a few of the more common ones. If you're having immense difficulty deciding which word to use, just plain "very big" might do.

Definitions of immense
1

adj unusually great in size or amount or degree or especially extent or scope

“the Los Angeles aqueduct winds like an immense snake along the base of the mountains”
immense numbers of birds”
“at vast (or immense) expense”
Synonyms:
Brobdingnagian, huge, vast
big, large
above average in size or number or quantity or magnitude or extent