From Longman Dictionary of Contemporary Englishcalm/cool etc exteriorcalm/cool etc exteriorAPPEARANCEbehaviour that seems calm, unfriendly etc but which often hides a different feeling or attitude Beneath that calm exterior, he has a fierce will to win. → exterior
Examples from the Corpus
calm/cool etc exterior• With her soft voice and her calm exterior, she absolutely would not let creditors off the hook.• Beneath his highly cool exterior he was anguished and distraught.• It all added up to the fact that below Silas's cool exterior there was warmth and compassion for others.• So you see, beneath that calm exterior lies a highly unstable child.• There is little or no hint of the compassion and humanity which lay beneath the cool exterior. 