diagnosticvsdiagnostiqueWhich spelling fits?

Quick tell: diagnostic is a noun, diagnostique is an adjective, so they fill different roles in a sentence.

Which to use

“diagnostic” is a noun and “diagnostique” is an adjective - they look or sound alike but fill different roles in a sentence.

#4,745
“diagnostic” frequency rank
#21,594
“diagnostique” frequency rank
26339
confusion score

Side-by-Side Comparison

Feature diagnostic diagnostique
Definition Partie de la médecine qui a pour objet la distinction des maladies, l'identification d’une maladie à partir de symptômes. Qui sert à établir le diagnostic d’une maladie.

Same sound, different letters: diagnostic vs diagnostique

Muted letters are shared; highlighted letters are the only spelling cue when pronunciation matches. Shared run: 9 letters. diagnostic runs 10 letters (CVVCCVCCVC) against diagnostique's 12 (CVVCCVCCVCVV) - the length gap alone is often enough to separate them once you know to check it.

10 ch
diagnostic
12 ch
diagnostique

Homophone desk: diagnostic vs diagnostique

Say them out loud and nothing separates them: diagnostic and diagnostique carry the same recorded pronunciation, \djaɡ.nɔs.tik\. Grammar is what tells them apart: one is anoun, the other anadjective, so most sentences will only accept one of them. They differ by 2 letter(s) in length. Our composite confusion score for this pair is 26339, derived from the frequency rank of both members and their visual similarity.

diagnostic is recorded at frequency rank #4,745, classified as anoun, pronounced \djaɡ.nɔs.tik\. diagnostique is at rank #21,594, tagged as anadj, pronounced \djaɡ.nɔs.tik\.

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 26339, this pair ranks #335,627 of 440,172 scored French confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of diagnostic vs diagnostique

Shared letters: adginost. Private to "diagnostic": c. Private to "diagnostique": equ.

"diagnostic" · 10 letters · shape CVVCCVCCVC  ·  "diagnostique" · 12 letters · shape CVVCCVCCVCVV

Known mistypes of this pair

  • diagnostic ← daignostic · ddiagnostic · diaggnostic · diagnnostic · diagnositc · diagnosstic · diagnostci · diagnosticc
  • diagnostique ← daignostique · ddiagnostique · diaggnostique · diagnnostique · diagnositque · diagnosstique · diagnostiqeu · diagnostiqque

Frequently Asked Questions

Is swapping "diagnostic" for "diagnostique" ever safe?
No - they are not even the same part of speech. "diagnostic" is a noun and "diagnostique" an adjective, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "diagnostic" or "diagnostique"?
"diagnostic" is the more common of the two: it sits at frequency rank #4,745 in our French list, against #21,594 for "diagnostique". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

You've separated the homophone pair "diagnostic" / "diagnostique". Follow the links when you need the full entry or a neighbour that trips the same ear.

  • Full dictionary entry for "diagnostic" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "diagnostique" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #335,627 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
  • "diagnostic" and "diagnostique" also get mixed up with nearby pairs, the highest-scored neighbour is "diagnostique vs diagnostiqués". 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 #335,627 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list