Which to use
“under” is a preposition and “undergo” is a verb - they look or sound alike but fill different roles in a sentence.
- #180
- “under” frequency rank
- #9,552
- “undergo” frequency rank
- 9732
- confusion score
Side-by-Side Comparison
| Feature | under | undergo |
|---|---|---|
| Definition | Beneath; below; at or to the bottom of, or the area covered or surmounted by. | To experience; to pass through a phase. |
Where the eye mixes under and undergo
Muted = shared; highlighted = the visual trap. They share 5 letters in sequence.
Why the eye confuses under with undergo
These two trip readers on the page rather than in the ear: under is /ˈʌndə/ while undergo is /ˌʌndɚˈɡoʊ/. Spoken aloud the problem disappears. In writing it persists, because they differ by 2 extra letter(s) - “under” sits inside “undergo”, and the parts of speech differ too (preposition vs verb), which is usually the fastest check. Our composite confusion score for this pair is 9732, derived from the frequency rank of both members and their visual similarity.
under is recorded at frequency rank #180, classified as aprep, pronounced /ˈʌndə/. undergo is at rank #9,552, tagged as averb, pronounced /ˌʌndɚˈɡoʊ/.
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 9732, this pair ranks #495,883 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.
Orthographic DNA of under vs undergo
Shared letters: denru. Private to "under": -. Private to "undergo": go.
"under" · 5 letters · shape VCCVC · "undergo" · 7 letters · shape VCCVCCV
Known mistypes of this pair
Frequently Asked Questions
Is swapping "under" for "undergo" ever safe?
Frequency check: "under" vs "undergo" - which ranks higher?
After this comparison
Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.
- Full dictionary entry for "under" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "undergo" - compare definitions side by side with the headword page. Word entry
- This pair ranks #495,883 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "under" and "undergo" also get mixed up with nearby pairs, the highest-scored neighbour is "under vs unsee". 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 #495,883 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.