l'air de rien znamená v Angličtina

poker face▼(any similar expression preventing giving away one's motives etc.)
noun
[UK: ˈpəʊk.ə.ˈfeɪs] [US: ˈpəʊk.ə.ˈfeɪs]

poker face▼(impassive facial expression preventing determining whether one's actions in the game are the result of a quality hand or of bluffing)
noun
[UK: ˈpəʊk.ə.ˈfeɪs] [US: ˈpəʊk.ə.ˈfeɪs]