What is the collective noun of plump?

There isn't a specific collective noun for "plump" objects. Collective nouns are usually used to describe groups of people or animals, like "a flock of birds" or "a herd of elephants".

To describe a group of plump objects, you could use descriptive phrases like:

* A cluster of plump grapes

* A bunch of plump peaches

* A collection of plump cushions

You could also use more general collective nouns like:

* A group of plump objects

* A collection of plump things

It depends on the specific context and the objects you're referring to.