What is another adjective for ill-smelling stale or musty?

Here are some adjectives that could describe an ill-smelling, stale, or musty odor:

Stronger, more negative:

* Foul

* Rank

* Noisome

* Putrid

* Fetid

* Malodorous

* Reeking

* Stench (used as a noun, but can also be used as an adjective)

More subtle, less harsh:

* Musty (already mentioned)

* Dusty

* Mildewy

* Damp

* Earthy

* Stale (already mentioned)

* Acrid (can describe a sharp, unpleasant smell)

* Fungus-like

The best adjective to use depends on the specific context and the intensity of the smell.