From King Dictionary of Contemporary English costly cost‧ly / ˈkɒstli $ ˈkɒːstli / ●●○ adjective 1 EXPENSIVE very expensive, especially wasting a lot of money a complex and costly procedure Such a database would be extremely costly to set up. ► see thesaurus at expensive 2 PROBLEM something that is costly causes a lot of problems or trouble His delay in making a decision could prove costly in the long run. — costliness noun [uncountable ] Examples from the Corpus costly • The finance committee rejected their plan because they said it was too costly. • Maximum use of state-of-the-art technology in place of costly and often error-prone personnel. • A lawsuit would be costly and we would probably lose. • Caring for the park's swans is a costly business - roughly $26,600 per year. • Convening production lines to largely automated production of flat panel sets would be costly in the short term. • Several of the gifts were costly, including a cup of gold and a crystal salt-set. • Taylor's pinched nerve has been the team's most costly injury this season. • Buying all those computers was a costly mistake. • From a cash-flow standpoint, that is less costly than actually paying your corporation an additional $ 200 in interest. • Yet the effort, far more costly than anything ever attempted by any government, has not produced the expected returns. • Purchase of market share is seen to be less costly than establishing brands - and is quicker too. • Punitive damages potentially could be much more costly to cigarette companies than compensatory damages. • Producers must receive a higher price to produce these more costly units. 7 Price and quantity supplied are directly related. prove costly • Dimas Teixeira's decision to stand off Beckham quickly proved costly. • Failure to protect yourself adequately could prove costly. • Still, there was, at times, an element of complacency in de Gaulle's approach, which proved costly. • Yet even now there is a sense of denial that could prove costly. • Mr Collin thinks that could prove costly and time consuming. • The war proved costly for both companies. • Vacant possession will be delayed and will prove costly, if not virtually impossible, to obtain. • Boeing Learns a Lesson in Predictability Mass layoffs prove costly in upswing when workers have taken skills, loyalty elsewhere.