rarefy

• POS: Verb (usu participle)
• HYPHEN: rar=e=fy

CIDE DICTIONARY

rarefy, v. t. [F. raréfier; L. rarus rare + -ficare (in comp.) to make; cf. L. rarefacere. See -fy.].

 To make rare, thin, porous, or less dense; to expand or enlarge without adding any new portion of matter to; -- opposed to condense.  [1913 Webster]

rarefy, v. i. 

 To become less dense; to become thin and porous.  Dryden.  [1913 Webster]

OXFORD DICTIONARY

rarefy, v. (-ies, -ied)
1 tr. & intr. make or become less dense or solid (rarefied air).
2 tr. purify or refine (a person's nature etc.).
3 tr. make (an idea etc.) subtle.

Derivative

rarefaction n. rarefactive adj. rarefication n.

Etymology

ME f. OF rarefier or med.L rarificare f. L rarefacere f. rarus rare + facere make

THESAURUS

rarefy

add to, adulterate, aggrandize, amplify, attenuate, augment, baptize, bloat, blow up, broaden, build, build up, bulk, bulk out, crescendo, cut, dematerialize, develop, dilate, dilute, disembody, distend, emacerate, emaciate, enervate, enlarge, etherealize, expand, extend, hike, hike up, huff, increase, inflate, irrigate, magnify, puff, puff up, pump, pump up, raise, reduce, sap, spiritualize, stretch, subtilize, sufflate, swell, thin, thin away, thin down, thin out, up, water, water down, weaken, widen

ROGET THESAURUS

rarefy

Expansion

VB become larger &c (large), expand, widen, enlarge, extend, grow, increase, incrassate, swell, gather, fill out, deploy, take open order, dilate, stretch, distend, spread, mantle, wax, grow up, spring up, bud, bourgeon, shoot, sprout, germinate, put forth, vegetate, pullulate, open, burst forth, gain flesh, gather flesh, outgrow, spread like wildfire, overrun, be larger than, surpass, render larger &c (large), expand, spread, extend, aggrandize, distend, develop, amplify, spread out, widen, magnify, rarefy, inflate, puff, blow up, stuff, pad, cram, exaggerate, fatten.

Rarity

VB rarefy, expand, dilate, subtilize.