rarefied

Short definition from Wiktionary

Adjective

1. 1
   Distant from the lives and everyday concerns of ordinary people; esoteric, exclusive, select.
2. 2
   Elevated in style or nature, sublime; of high intellectual or moral value.
3. 3
   Less dense than usual; thin.

Verb

1. 1
   simple past and past participle of rarefy