What does costliest mean?
"Costliest" is the superlative form of the adjective "costly," used to describe whatever carries the greatest price, expense, or sacrifice within a given group. It operates on two levels: literally, it identifies the most expensive item, as in "the costliest house on the street," while figuratively it signals the gravest consequences, as in "the costliest mistake of his career" or "the costliest battle of the war." This dual usage makes it especially common in journalism, history, and finance, where writers rank disasters, conflicts, and errors by their toll in money or lives. The word derives ultimately from the Latin "constare," meaning to stand at or cost, via Old French. Slightly more formal than "most expensive," it conveys weight and seriousness, and it is typically paired with nouns like mistake, disaster, war, lesson, and victory. Understanding it helps readers grasp both commercial and moral dimensions of price.
adjectiveSuperlative of "costly"; most expensive in price, value, or the sacrifice required.
- Most expensive in monetary terms; commanding the highest price.
- Involving the greatest loss, damage, or sacrifice (e.g., the costliest war, the costliest mistake).
"The diamond necklace was the costliest item ever sold at the auction house."
"Hurricane Katrina remains one of the costliest natural disasters in American history."
"Choosing the cheapest supplier turned out to be the costliest decision the company ever made."
The word "cost" comes from the Latin "constare" — to stand firm — so the costliest things are literally the ones that demand you stand up and pay.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of costliest
The adjective "costly" was formed in Middle English from the noun "cost" plus the suffix "-ly," and "costliest" is its regular superlative. "Cost" itself entered English through Old French "coster" (to cost), from the Late Latin verb "constare," meaning "to stand at a price," built on Latin "stare" (to stand). The same Latin root gave English "constant" and related words such as "consistent" and "existence." The figurative sense of costly — involving great loss rather than literal money — developed alongside the monetary one and is well established by the early modern period.
Related word forms
How costliest is actually used
"Costliest" works both literally (highest price) and figuratively (greatest loss or consequence), and it frequently appears in news reporting about disasters, wars, and financial losses. It is slightly more formal than "most expensive."
Easily confused with costliest
"Coastliest" is not a standard English word; "costliest" refers to expense or sacrifice, not coasts.
"Costlier" is the comparative form (more expensive of two things), while "costliest" is the superlative (most expensive of three or more).