Man is described as a vegetable being in a metaphorical sense, suggesting that he is passive, unresponsive, or lacking in vitality. This comparison implies that the person is not actively engaging with the world or showing any signs of growth or development. It can also suggest a sense of being stagnant or unchanging, like a vegetable that remains rooted in one place. Overall, describing someone as a vegetable being is a way of highlighting their lack of energy, motivation, or agency in their life.