costing much; expensive; high in price

a costly emerald bracelet; costly medical care.

resulting in great expense

The upkeep of such a large house is costly.

resulting in great detriment

It was a costly mistake because no one ever trusted him again.

of great value; very valuable; sumptuous.

lavish; extravagant.

adjective

cheap , inexpensive , reasonable , not valuable , poor , aiding , helpful

adjective

an arm and leg , cher , dear , excessive , executive , exorbitant , extortionate , extravagant , fancy , high , highly priced , high-priced , inordinate , precious , premium , pricey , steep , stiff * , top , valuable , gorgeous , inestimable , invaluable , lavish , luxurious , opulent , rich , splendid , sumptuous , catastrophic , deleterious , disastrous , loss-making , ruinous , sacrificial , expensive , priceless , worthy , damaging