Literal translation: to be in the moonFigurative translation: to daydream, to pay zero attention. \n \n This is easy to guess, right? Sometimes, French also use this for the same meaning: être tête en l'air - which literally means 'head in the air,' but actually means 'to be distracted'. \n \n X: Est-ce que tu as compris ce que je viens de te dire?Y: Quoi? Désolée, j'étais dans la lune.