Which to use
“spi” is an adjective and “sub” is a preposition - they look or sound alike but fill different roles in a sentence.
- #49,369
- “spi” frequency rank
- #10,413
- “sub” frequency rank
- 59782
- confusion score
Side-by-Side Comparison
| Feature | spi | sub |
|---|---|---|
| Definition | Spirituel (au sens religieux). | Préposition latine, qui s’emploie dans des locutions telles que : |
Where the eye mixes spi and sub
Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.
Why the eye confuses spi with sub
These two trip readers on the page rather than in the ear: spi is \spi\ while sub is \syb\. Spoken aloud the problem disappears. In writing it persists, because they share most of their letters but differ in 2 positions, and the parts of speech differ too (adjective vs preposition), which is usually the fastest check. Our composite confusion score for this pair is 59782, derived from the frequency rank of both members and their visual similarity.
spi is recorded at frequency rank #49,369, classified as anadj, pronounced \spi\. sub is at rank #10,413, tagged as aprep, pronounced \syb\.
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 59782, this pair ranks #101,209 of 440,172 scored French confusable pairs - among the most confusable pairs.
Orthographic DNA of spi vs sub
Shared letters: s. Private to "spi": ip. Private to "sub": bu.
"spi" · 3 letters · shape CCV · "sub" · 3 letters · shape CVC
Frequently Asked Questions
Do "spi" and "sub" mean the same thing in a sentence?
Which is more common, "spi" or "sub"?
Useful next steps
Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.
- Full dictionary entry for "spi" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "sub" - compare definitions side by side with the headword page. Word entry
- This pair ranks #101,209 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
- "spi" and "sub" also get mixed up with nearby pairs, the highest-scored neighbour is "spi vs suu". Nearby pair
Confusion rank #101,209 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.