- of great price or value; expensive
- entailing great loss or sacrifice: a costly victory
- splendid; lavish
WordReference Random House Learner's Dictionary of American English © 2026
cost•ly /ˈkɔstli, ˈkɑst-/USA pronunciation
adj., -li•er, -li•est.
WordReference Random House Unabridged Dictionary of American English © 2026- costing much;
high in price:a costly mink coat. - resulting in great loss:a costly mistake.
cost•ly
(kôst′lē, kost′-),USA pronunciation adj., -li•er, -li•est.
cost′li•ness, n.
- 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.
- Middle English costli. See cost1, -ly 1350–1400
- 1. dear, high-priced. See expensive.
Collins Concise English Dictionary © HarperCollins Publishers::
costly /ˈkɒstlɪ/ adj ( -lier, -liest)
'costly' also found in these entries (note: many are not synonyms or translations):
expensive
- frugal
- Gallipoli
- plush
- precious
- rich
- sumptuous
- treasure
- alloy
- Berezina
- bone-crushing
- cabin class
- chargeful
- cheap
- conspicuous consumption
- depth
- endear
- engagement
- fancy
- folly
- former
- gold plate
- gold-plating
- high
- high-priced
- inexpensive
- job
- land bridge
- poison pill
- priceless
- psychic bid
- pyrrhic
- Pyrrhic victory
- third class
- tight
- tourist class
- trouble
- upscale
- second class
- set
- splurge