ˈkȯstlē, -li also ˈkäs-, rap. -s(t)l- adjective
( -er/-est )
Etymology: Middle English, from cost (I) + -ly
1. : of great cost or value : fine , rich , splendid
they are clad in very costly robes of silk; they are girdled like queens — Lafcadio Hearn
2. : involving excessive expenditure : necessitating considerable loss or sacrifice
to encourage me in litigation and to make it as protracted and costly as he can — G.B.Shaw
3. : extravagant , prodigal , lavish
costly entertainment
costly habits
Synonyms:
costly , expensive , dear , valuable , precious , invaluable , priceless : costly stresses high price and may suggest elegance, sumptuousness, or luxury
the curtains and upholstery of the chairs and sofas and the hangings of my bed are of the costliest and most beautiful fabrics, and must have been of fabulous value when they were made — Bram Stoker
walls, columns, and arches seem a quarry of precious stones, so beautiful and costly are the marbles with which they are inlaid — Nathaniel Hawthorne
expensive may imply a cost above a purchaser's means or above intrinsic valuation
the father was unable to give the child as expensive an education as he had desired — J.A.Froude
dear indicates a high cost, often one greatly increased because of scarcities
the lively affection seamen have for strong drink is well known; but in the South Seas, where it is so seldom to be had, a thoroughbred sailor deems scarcely any price too dear which will purchase his darling “tot” — Herman Melville
valuable may suggest hope or chance or great gain or usefulness or of high price in sale or exchange
how valuable these lands were to become Congress could hardly guess, nor did it suspect that the grants in the northern part of the state were to be worth millions in timber and iron — American Guide Series: Minnesota
precious may stress extremely great value, often value brought about by rareness or scarcity
a precious thing, a treasure beyond diamonds or rubies — Jack London
we of the Bounty's launch had been so accustomed to thinking of wine and spirits as the most precious of commodities, to be taken only a spoonful at a time — C.B.Nordhoff & J.N.Hall
In other than monetary matters, these words keep more or less the same connotations costly , dear , and expensive may describe great expenditure of resources, materials, or effort
in order to finance the ever more costly equipment and maintenance of the new paid soldiery, the rulers of Europe had recourse to the financier — Lewis Mumford
their stout resistance was destined to cost them dear … many thousand citizens were ruined, many millions of property confiscated — J.L.Motley
dear and precious are often used in matters of emotion
and measureless sweet I deem her, and dear she is to mine eyes — William Morris
his child, his precious possession — W.F.de Morgan
precious Savior, still our refuge — Joseph Scriven
valuable often describes things or conditions quite advantageous or useful
that the release of the information at the time it is received will not prove valuable to the enemy — F.D.Roosevelt
invaluable and priceless may decribe any thing or condition of such great worth that evaluation is practically impossible
this invaluable liquor was of a pale golden hue, like other of the rarest Italian wines — Nathaniel Hawthorne
control of the sea was a priceless asset to the Union, the navy maintained communications with Europe, cut off those of the South, captured important coastal cities — S.E.Morison & H.S.Commager