Which to use
“undertake” and “undertaken” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.
- #10,787
- “undertake” frequency rank
- #9,001
- “undertaken” frequency rank
- 19788
- confusion score
Side-by-Side Comparison
| Feature | undertake | undertaken |
|---|---|---|
| Definition | To take upon oneself; to start, to embark on (a specific task etc.). | past participle of undertake |
Where the eye mixes undertake and undertaken
Muted = shared; highlighted = the visual trap. They share 9 letters in sequence. undertake runs 9 letters (VCCVCCVCV) against undertaken's 10 (VCCVCCVCVC) - the length gap alone is often enough to separate them once you know to check it.
Visual trap between undertake and undertaken
A purely visual mix-up. undertake (/ˌʌndəˈteɪk/) and undertaken (/ʌndə(ɹ)ˈteɪkən/) are said differently, so reading them aloud is the quickest way to catch the wrong one. On the page they stay close: they differ by 1 extra letter(s) - “undertake” sits inside “undertaken”. Our composite confusion score for this pair is 19788, derived from the frequency rank of both members and their visual similarity.
undertake is recorded at frequency rank #10,787, classified as averb, pronounced /ˌʌndəˈteɪk/. undertaken is at rank #9,001, tagged as averb, pronounced /ʌndə(ɹ)ˈteɪkən/.
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 19788, this pair ranks #435,697 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.
Orthographic DNA of undertake vs undertaken
Shared letters: adeknrtu. Private to "undertake": -. Private to "undertaken": -.
"undertake" · 9 letters · shape VCCVCCVCV · "undertaken" · 10 letters · shape VCCVCCVCVC
Known mistypes of this pair
- undertake ← nudertake · udnertake · unddertake · underatke · underrtake · undertaek · undertakke · undertkae
- undertaken ← nudertaken · udnertaken · unddertaken · underatken · underrtaken · undertaekn · undertakenn · undertakken
Frequently Asked Questions
Is swapping "undertake" for "undertaken" ever safe?
Frequency check: "undertake" vs "undertaken" - 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 "undertake" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "undertaken" - compare definitions side by side with the headword page. Word entry
- This pair ranks #435,697 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "undertake" and "undertaken" also get mixed up with nearby pairs, the highest-scored neighbour is "undertake vs undertone". 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 #435,697 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.