Many Without a Direct Noun

Many and much are be used as adjectives.  When used to modify another adjective, much is used because the second adjective is always uncountable, just like a noun. Most of the time, it is used this way in comparisons, so look for words like more and less, or suffixes like ‑ier.

The white cat is many more amusing than the brown cat.

Many is modifying more, but more is uncountable, so the first adjective needs to be changed to much.

The white cat is much more amusing than the brown cat.

Are these purple jeans many less expensive than the black ones?

Are these purple jeans much less expensive than the black ones?

Tom is many funnier than Mary.

Tom is much funnier than Mary.