Let's break down why:
* "Eating" is a verb (present participle form), usually used to describe an action.
* "Generosity" is a noun, representing a quality or trait.
The phrase tries to combine these two words in a way that doesn't make grammatical sense. To make this into a meaningful phrase, we need to rephrase it. For example:
* "The act of eating with generosity"
* "The generosity of the eaters"
In these phrases, the words are used correctly, and we can determine their parts of speech:
* "Act" is a noun.
* "Eating" is a noun (gerund, acting as the object of the preposition "of").
* "Generosity" is a noun.
* "Eaters" is a noun.