Which to use
“costly” and “cosy” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.
- #7,899
- “costly” frequency rank
- #19,301
- “cosy” frequency rank
- 27200
- confusion score
Side-by-Side Comparison
| Feature | costly | cosy |
|---|---|---|
| Definition | Of high cost; expensive. | Affording comfort and warmth; snug; social and comfortable. |
Where the eye mixes costly and cosy
Muted = shared; highlighted = the visual trap. They share 4 letters in sequence. costly runs 6 letters (CVCCCV) against cosy's 4 (CVCV) - the length gap alone is often enough to separate them once you know to check it.
Visual trap between costly and cosy
A purely visual mix-up. costly (/ˈkɒst.li/) and cosy (/ˈkəʊzi/) are said differently, so reading them aloud is the quickest way to catch the wrong one. On the page they stay close: they differ by 2 letter(s) in length. Our composite confusion score for this pair is 27200, derived from the frequency rank of both members and their visual similarity.
costly is recorded at frequency rank #7,899, classified as anadj, pronounced /ˈkɒst.li/. cosy is at rank #19,301, tagged as anadj, pronounced /ˈkəʊzi/.
Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.
With a confusion score of 27200, this pair ranks #380,783 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of costly vs cosy
Shared letters: cosy. Private to "costly": lt. Private to "cosy": -.
"costly" · 6 letters · shape CVCCCV · "cosy" · 4 letters · shape CVCV
Known mistypes of this pair
Frequently Asked Questions
Can "costly" and "cosy" be used interchangeably?
Which is more common, "costly" or "cosy"?
Useful next steps
Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.
- Full dictionary entry for "costly" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "cosy" - compare definitions side by side with the headword page. Word entry
- This pair ranks #380,783 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "costly" and "cosy" also get mixed up with nearby pairs, the highest-scored neighbour is "cosy vs cuny". Nearby pair
- Recorded mistypes exist for at least one side of this pair, useful when a spell-checker or OCR lands on the wrong form. See mistypes
Confusion rank #380,783 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.