undergroundon Elementaryalso onCEFR Advanced (C1)? Band 2 (BND2)? باطِن,باطِنِيّ,جَوْفِيّ,خَفِيّ,سِرّيّ,مَطْمُور underground underground(adjective) باطِن,باطِنِيّ,جَوْفِيّ,خَفِيّ,سِرّيّ,مَطْمُور Forms adjective underground