The first noun/adjective pair is about *having* a lot. The second is about willingness to *give* a lot.

Just one small additional tip, Mraz: Don't forget to use the article "the" in English. E.g. "What is THE difference between" ;) great question!

Both are quite similar. I would associate "generous and show generosity (give freely)" more with a person. Bounty is more similar to "abundance" (as state of being). For example: The bounty of nature. Have a look at https://www.merriam-webster.com/dictionary/bountiful. Hope this helps!

bounty and generosity are nouns whereas bountiful and genereous are adjectives