The Hebrew verb nuwb means to bear fruit, to flourish, to increase, or to prosper. It describes the productive growth of plants and trees, and by extension, the prosperous fruitfulness of the righteous life. The related noun niv means fruit or produce.
In the Psalms, nuwb describes the enduring fruitfulness of the righteous even in old age, demonstrating that spiritual vitality does not diminish with physical aging. This verb connects to the broader biblical theme that those rooted in God's house will continually produce fruit, reflecting the faithfulness of the LORD throughout all seasons of life.