WordNet sense 1 (having low density):

rare, rarefied

WordNet sense 2 (relatively thin in consistency or low in density; not viscous):

thin

WordNet sense 3 (set aside for the use of a particular person or party):

reserved

WordNet sense 4 (of high moral or intellectual value; elevated in nature or style):

exalted, grand, high-flown, high-minded, idealistic, lofty, sublime, noble-minded

WordNet sense 5 (having or showing or indicative of high or elevated character):

noble