[ kawst-lee, kost- ]
/ ˈkɔst li, ˈkɒst- /

adjective, cost·li·er, cost·li·est.

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.

Origin of costly

First recorded in 1350–1400, costly is from the Middle English word costli. See cost, -ly

synonym study for costly

1. See expensive.


cost·li·ness, nouno·ver·cost·li·ness, nouno·ver·cost·ly, adjectiveun·cost·ly, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Example sentences from the Web for costly

British Dictionary definitions for costly

/ (ˈkɒstlɪ) /

adjective -lier or -liest

of great price or value; expensive
entailing great loss or sacrificea costly victory
splendid; lavish

Derived forms of costly

costliness, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012