adjective, cost·li·er, cost·li·est.
- costoaxillary vein,
- costocervical artery
Origin of costly
Examples from the Web for costliest
Child care is probably the costliest part of having a severely disabled child.
If estimates come in at the higher end of the range, it could be the costliest since Hurricane Katrina.As Much of New York and New Jersey Remain Paralyzed and Devastated, the Costs From Sandy Continue to Climb|Matthew Zeitlin|November 2, 2012|DAILY BEAST
The race features two mega-millionaires, in a contest that promises to be one of the costliest in American history.
But our employer-based system already delivers the costliest health care on the planet.
Some of the biggest and costliest buildings in New York and Chicago are built on ground leases.The City of Numbered Days|Francis Lynde
It is the stateliest and the costliest ever erected to the memory of any man.The Letters Of Mark Twain, Volume 2, 1867-1875|Mark Twain (Samuel Clemens)
It was in this war, too, that the Mikado's soldiers strung the costliest of all telephone lines, at 203 Metre Hill.The History of the Telephone|Herbert N. Casson
This gentleman is the costliest of guests in life, and we shall look very blank if we have nothing to set before him.The Empress Frederick; a memoir|Anonymous
Whereas the fact is that a great many of the costliest gifts in this season do not count at all.The Complete Essays of C. D. Warner|Charles Dudley Warner