rarefied (Adjective) — Having low density. ex. "lightheaded from the rarefied mountain air"
rarefied (Adjective) — Of high moral or intellectual value; elevated in nature or style.
rarefied (Verb) — Lessen the density or solidity of. ex. "The bones are rarefied"
rarefied (Verb) — Make more subtle or refined.
rarefied (Verb) — (chemistry) weaken the consistency of (a chemical substance).