The Oxford Thesaurus An A-Z Dictionary of Synonyms - rarefiedadj.

1) thin, lean, attenuated, diluted, sparse, scant, scanty: As we climbed higher, the rarefied atmosphere made breathing more difficult. 2) exalted, lofty, elevated, high, sublime, noble, high: I feel out of place in the rarefied atmosphere of academia. 3) cliquish, clannish, exclusive, private, select, esoteric: Clarence copes well in the rarefied atmosphere of Whitehall's corridors of power.