rarified

adjectives

having low density
"rare gasses"; "lightheaded from the rarefied mountain air"
rare, rarefied, rarified
of high moral or intellectual value; elevated in nature or style
"an exalted ideal"; "argue in terms of high-flown ideals"- Oliver Franks; "a noble and lofty concept"; "a grand purpose"
elevated, exalted, grand, high-flown, high-minded, idealistic, lofty, noble-minded, rarefied, rarified, sublime