sad vs si, What's the Difference?

Which to use

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

#13,385
“sad” frequency rank: #482
“si” frequency rank: 13867
confusion score

Side-by-Side Comparison

Feature	sad	si
Definition	triste	refere-se à terceira pessoa, indica reflexividade e é usado após preposição (a, de, em, contra, sobre, por, etc., exceto com)

Where the eye mixes sad and si

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

3 ch

sad

2 ch

Why the eye confuses sad with si

These two trip readers on the page rather than in the ear: sad is /sæd/ while si is /ˈsi/. 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 pronoun), which is usually the fastest check. Our composite confusion score for this pair is 13867, derived from the frequency rank of both members and their visual similarity.

sad is recorded at frequency rank #13,385, classified as anadj, pronounced /sæd/. si is at rank #482, tagged as apron, pronounced /ˈsi/.

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 13867, this pair ranks #58,347 of 75,631 scored Portuguese confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of sad vs si

Shared letters: s. Private to "sad": ad. Private to "si": i.

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

Frequently Asked Questions

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

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

In ordinary Portuguese text, does "sad" or "si" show up more?

"si" is the more common of the two: it sits at frequency rank #482 in our Portuguese list, against #13,385 for "sad". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

Useful next steps

Eye-level mix-up between "sad" and "si" is sorted above. Next: full entries or other pairs that share a letter shape.

Full dictionary entry for "sad" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "si" - compare definitions side by side with the headword page. Word entry
This pair ranks #58,347 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
"sad" and "si" also get mixed up with nearby pairs, the highest-scored neighbour is "sad vs soap". Nearby pair

Confusion rank #58,347 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.