sem vs su, What's the Difference?

Which to use

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

#69
“sem” frequency rank: #6,713
“su” frequency rank: 6782
confusion score

Side-by-Side Comparison

Feature	sem	su
Definition	indicativa de carência ou ausência	dele

Letter map: sem vs su

Shared letters muted; letters that set sem and su apart highlighted. Shared run: 1.

3 ch

sem

2 ch

Role in the sentence - sem and su

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: sem is apreposition and suanadjective. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 6782, derived from the frequency rank of both members and their visual similarity.

sem is recorded at frequency rank #69, classified as aprep, pronounced /sɐ̃j̃/. su is at rank #6,713, tagged as anadj.

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 6782, this pair ranks #67,548 of 75,631 scored Portuguese confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of sem vs su

Shared letters: s. Private to "sem": em. Private to "su": u.

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

Frequently Asked Questions

Do "sem" and "su" mean the same thing in a sentence?

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

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

"sem" is the more common of the two: it sits at frequency rank #69 in our Portuguese list, against #6,713 for "su". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

After this comparison

Pair "sem" vs "su" is on the table, pick a follow-up below.

Full dictionary entry for "sem" 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 #67,548 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
"sem" and "su" also get mixed up with nearby pairs, the highest-scored neighbour is "Sau vs su". Nearby pair

Confusion rank #67,548 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.