Anything that has a strong scent can be described as odorous. Usually if you say something is odorous you mean that it smells unpleasant — like an odorous blue cheese made from unpasteurized milk.
The adjective odorous comes from the Latin odorus, meaning “fragrant.” Typically, you wouldn’t say, “those roses you sent me are so odorous!” Although that comment could be literally correct, the implication would be insulting to the giver of said roses. More common uses of odorous might include: odorous gym mats, odorous garbage can, odorous gas fumes — you get the picture. Or rather the stench.