sadvssuTell them apart

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

Which to use

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

#1,536
“sad” frequency rank
#8,094
“su” frequency rank
9630
confusion score

Side-by-Side Comparison

Feature sad su
Definition Emotionally negative. Alternative form of xu (“former Vietnamese currency”).

Letter map: sad vs su

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

3 ch
sad
2 ch
su

Role in the sentence - sad and su

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: sad is anadjective and suanoun. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 9630, derived from the frequency rank of both members and their visual similarity.

sad is recorded at frequency rank #1,536, classified as anadj, pronounced /ˈsæd/. su is at rank #8,094, 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 9630, this pair ranks #496,397 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.

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 noun, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "sad" or "su"?
"sad" is the more common of the two: it sits at frequency rank #1,536 in our English list, against #8,094 for "su". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

After this comparison

Done with this confusable. These links stay specific to "sad" and "su".

  • 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 #496,397 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "sad" and "su" also get mixed up with nearby pairs, the highest-scored neighbour is "su vs sura". Nearby pair

Confusion rank #496,397 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