costly
/ˈkɒst.li/adjective, noun
costly is spelled C-O-S-T-L-Y: 6 letters and 2 syllables. It appears 8.5 times per million words in written English, the 7,910th most frequent word form (wordfreq, 2021 data). As an adjective, costly means “Of high cost; expensive” (English Wiktionary, September 2026).
How many letters and syllables are in costly?
| Letters | 6: C-O-S-T-L-Y |
|---|---|
| Syllables | 2 (from its American pronunciation) |
| In writing | 8.5 times per million words; the 7,910th most frequent word form |
| Wrong spellings searched | none measured in search |
Sources: letters and syllables from the English Wiktionary's hyphenation or pronunciation and the CMU Pronouncing Dictionary; written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
How common is costly?
Costly appears 8.5 times per million words in written English, the 7,910th most frequent word form in the list.
Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
How do you pronounce costly?
- UK /ˈkɒst.li/
Costly has 2 syllables (counted from its American pronunciation in the CMU Pronouncing Dictionary).
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Recordings: En-us-costly.ogg, Wikimedia Commons (author and licence on each file's page).
Forms of costly
- costlier comparative
- more costly comparative
- costliest superlative
- most costly superlative
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
What does costly mean?
The meanings the English Wiktionary records, quoted as written there (source below).
adjective
- 1
Of high cost; expensive.
a costly activity
noun
- 1
Short for costly colours.
Costly is a simpler game than cribbage.
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
Costly in Spanish, French, German and Portuguese
In the sense expensive:
| Language | Words |
|---|---|
| French | coûteux, lourd |
| German | teuer, kostspielig |
| Portuguese | custoso, caro |
| Spanish | costoso, caro |
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Translations are Wiktionary's, by sense; a linked word has its own PlainSpell page.
Where does costly come from?
From Middle English costly, costely, costeley, equivalent to cost + -ly.
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).