What do you mean someone is grounded?

To put it bluntly, "grounding gas" means to have extensive contact with the people, integrate with the broadest masses of the people, and reflect the wishes, demands and interests of the people at the bottom. You can't let yourself stand on top and be divorced from the actual needs and real wishes of the masses. It is not superficial, but down-to-earth and deeply rooted in the hearts of the people. It is to follow the laws of nature, not to act blindly. (This is the explanation of Baidu Encyclopedia)

Therefore, there is an extended meaning that saying that a person is grounded actually means popularization. Take a joke seen in Weibo as an example:

If I can't get married, my brother will comfort me: I believe that one day, a tasteful and grounded female diaosi who listens to Divine Comedy and only watches idol dramas like you will be married by a tall and powerful man wearing a thick gold necklace and driving a bass motorcycle. . . Divine comedy and idol drama are popular enough. )