sthvsSuiTell them apart

Quick tell: sth is a pronoun, Sui is a name, so they fill different roles in a sentence.

Which to use

“sth” is a pronoun and “Sui” is a name - they look or sound alike but fill different roles in a sentence.

#40,035
“sth” frequency rank
#28,040
“Sui” frequency rank
68075
confusion score

Side-by-Side Comparison

Feature sth Sui
Definition Abbreviation of something. The Sui dynasty of China which ruled from 581 to 618.

Letter map: sth vs Sui

Shared letters muted; letters that set sth and Sui apart highlighted. Shared run: 1.

3 ch
sth
3 ch
Sui

Grammar separator: sth vs Sui

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: sth is apronoun and Suianame. On the page they share most of their letters but differ in 2 positions. Our composite confusion score for this pair is 68075, derived from the frequency rank of both members and their visual similarity.

sth is recorded at frequency rank #40,035, classified as apron. Sui is at rank #28,040, tagged as aname, pronounced /sweɪ/.

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 68075, this pair ranks #60,519 of 530,003 scored English confusable pairs - among the most confusable pairs.

Orthographic DNA of sth vs Sui

Shared letters: s. Private to "sth": ht. Private to "Sui": iu.

"sth" · 3 letters · shape CCC  ·  "Sui" · 3 letters · shape CVV

Frequently Asked Questions

Is swapping "sth" for "Sui" ever safe?
No - they are not even the same part of speech. "sth" is a pronoun and "Sui" a name, so a sentence built for one is usually ungrammatical with the other.
In ordinary English text, does "sth" or "Sui" show up more?
"Sui" is the more common of the two: it sits at frequency rank #28,040 in our English list, against #40,035 for "sth". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

Pair "sth" vs "Sui" is on the table, pick a follow-up below.

  • Full dictionary entry for "sth" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "Sui" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #60,519 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "sth" and "Sui" also get mixed up with nearby pairs, the highest-scored neighbour is "Sif vs sth". Nearby pair

Confusion rank #60,519 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.

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

Source: FrequencyWords open word-frequency list