* Form: This is a noun by itself, meaning a shape or structure.
* Foe: This is also a noun, meaning an enemy or opponent.
* Strident: This is an adjective, describing something harsh or loud. There isn't a direct noun form of "strident" in the English language. However, you could use the noun stridency to refer to the quality of being strident.
So, the nouns are:
* Form
* Foe
* Stridency (if referring to the noun form of "strident")