staidvsSTIWhich spelling fits?

Quick tell: staid is a adjective, STI is a noun, so they fill different roles in a sentence.

Which to use

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

#48,507
“staid” frequency rank
#26,266
“STI” frequency rank
74773
confusion score

Side-by-Side Comparison

Feature staid STI
Definition Not capricious or impulsive; sedate, serious, sober. Initialism of sexually transmitted infection (also S.T.I.).

Letter map: staid vs STI

Shared letters muted; letters that set staid and STI apart highlighted. Shared run: 3.

5 ch
staid
3 ch
STI

Part-of-speech tell for staid / STI

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: staid is anadjective and STIanoun. On the page they differ by 2 letter(s) in length. Our composite confusion score for this pair is 74773, derived from the frequency rank of both members and their visual similarity.

staid is recorded at frequency rank #48,507, classified as anadj, pronounced /steɪd/. STI is at rank #26,266, tagged as anoun.

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 74773, this pair ranks #35,256 of 530,003 scored English confusable pairs - among the most confusable pairs.

Orthographic DNA of staid vs STI

Shared letters: ist. Private to "staid": ad. Private to "STI": -.

"staid" · 5 letters · shape CCVVC  ·  "STI" · 3 letters · shape CCV

Known mistypes of this pair

  • staidsatid · sstaid · stadi · staidd · stiad · sttaid · tsaid

Frequently Asked Questions

Is swapping "staid" for "STI" ever safe?
No - they are not even the same part of speech. "staid" is an adjective and "STI" a noun, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "staid" or "STI"?
"STI" is the more common of the two: it sits at frequency rank #26,266 in our English list, against #48,507 for "staid". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

After this comparison

Pair "staid" vs "STI" is on the table, pick a follow-up below.

  • Full dictionary entry for "staid" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "STI" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #35,256 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "staid" and "STI" also get mixed up with nearby pairs, the highest-scored neighbour is "Sajid vs staid". 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 #35,256 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