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