What's the plural form of vainglory? Here's the word you're looking for.
Answer
The noun vainglory can be countable or uncountable.
In more general, commonly used, contexts, the plural form will also be vainglory.
However, in more specific contexts, the plural form can also be vainglories e.g. in reference to various types of vainglories
or a collection of vainglories.