rar·e·fied 
/ˈrerəˌfaɪd/ adjective
/ˈrerəˌfaɪd/ adjective [more rarefied; most rarefied] 1 often disapproving : understood by only a small group of people : only for people who know about a particular thing
▪ She has never been comfortable in the rarefied [=esoteric] world of art dealers. 2 technical, of air : not having much oxygen because of being high up in the atmosphere
▪ It's difficult to breathe in the rarefied air near the mountain's peak.
▪ She has never been comfortable in the rarefied [=esoteric] world of art dealers.
▪ It's difficult to breathe in the rarefied air near the mountain's peak.
