The phrase "be up in clouds" refers to someone who is lost in dreams, not paying attention to reality. The antonyms for this phrase would be "grounded," "practical," "realistic," and "down-to-earth." These words represent the opposite of being lost in one's thoughts and instead focus on the present and the practical aspects of a situation. A grounded person is someone who is centered and level-headed, while a practical person is someone who focuses on finding viable solutions to problems. Being realistic means seeing things as they are, not as we want them to be, and being down-to-earth means having a practical and pragmatic approach to life.