rarefy /'resnfai; 'rerajai/ vt, vi (pt, pp -fied) [VP6A, 2A] make or become less dense; purify: 使或變?yōu)橄”? 使純凈; 使純： the rarefied air of the mountain tops; 山頂上變稀薄的空氣; refine; make subtle: 凈化; 精煉： rarefied ideas/theories. 千鐘百煉的思想(理論)。 rare-faction /, /rean'faekjn; , rrrs-'fkjan n [U] ~ing. 使或變?yōu)橄”? 使純凈; 精煉。