The phrase "be plentiful" refers to the abundance or plentifulness of something. There are many synonyms for this phrase, some of which include overflowing, abundant, copious, ample, bountiful, generous, and profuse. These words all convey the idea that something is more than enough or in great quantity. For example, you might say that the fruit at the farmer's market was overflowing with ripe, juicy options. Or you might describe a holiday feast as bountiful, with a wide variety of delicious foods to choose from. No matter which synonym you choose, they all indicate a rich and plentiful abundance.