sad vs su, What's the Difference?

Which to use

“sad” is an adjective and “su” is a verb - they look or sound alike but fill different roles in a sentence.

#26,525
“sad” frequency rank: #1,609
“su” frequency rank: 28134
confusion score

Side-by-Side Comparison

Feature	sad	su
Definition	Triste.	Participe passé masculin singulier du verbe savoir.

Where the eye mixes sad and su

Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.

3 ch

sad

2 ch

Why the eye confuses sad with su

These two trip readers on the page rather than in the ear: sad is \sæd\ while su is \sy\. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 letter(s) in length, and the parts of speech differ too (adjective vs verb), which is usually the fastest check. Our composite confusion score for this pair is 28134, derived from the frequency rank of both members and their visual similarity.

sad is recorded at frequency rank #26,525, classified as anadj, pronounced \sæd\. su is at rank #1,609, tagged as averb, pronounced \sy\.

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 28134, this pair ranks #324,708 of 440,172 scored French confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of sad vs su

Shared letters: s. Private to "sad": ad. Private to "su": u.

"sad" · 3 letters · shape CVC · "su" · 2 letters · shape CV

Frequently Asked Questions

Can "sad" and "su" be used interchangeably?

No - they are not even the same part of speech. "sad" is an adjective and "su" a verb, so a sentence built for one is usually ungrammatical with the other.

Which is more common, "sad" or "su"?

"su" is the more common of the two: it sits at frequency rank #1,609 in our French list, against #26,525 for "sad". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

After this comparison

Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.

Full dictionary entry for "sad" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "su" - compare definitions side by side with the headword page. Word entry
This pair ranks #324,708 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
"sad" and "su" also get mixed up with nearby pairs, the highest-scored neighbour is "sad vs suu". Nearby pair

Confusion rank #324,708 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.