IPA: /ˈplɛntɪfəl.nəs/
KK: /ˈplɛntɪfəlnəs/
A state of having a large amount of something; an abundance or a lot of something.
The plentifulness of food during the harvest season made everyone happy.
Plentifulness is formed from "plentiful" (from Middle English *plentifull*, meaning abundant) and the suffix "-ness" (meaning the state or quality of). The word refers to the state of being abundant or having a lot of something.
Think of 'plentiful' meaning abundant, and remember that '-ness' indicates a state or quality. So, plentifulness is the quality of being abundant.