Which to use
“underline” is a noun and “undermine” is a verb - they look or sound alike but fill different roles in a sentence.
- #29,874
- “underline” frequency rank
- #12,161
- “undermine” frequency rank
- 42035
- confusion score
Side-by-Side Comparison
| Feature | underline | undermine |
|---|---|---|
| Definition | A line placed underneath a piece of text in order to provide emphasis or to indicate that it should be viewed in italics or (in electronic documents) that it acts as a hyperlink. | To dig underneath (something), to make a passage for destructive or military purposes; to sap. |
Where the eye mixes underline and undermine
Muted = shared; highlighted = the visual trap. They share 8 letters in sequence. underline and undermine follow the identical consonant-vowel pattern (VCCVCCVCV). Same shape at a glance is often the real trap, independent of shared letters.
Look-alike desk: underline vs undermine
These two trip readers on the page rather than in the ear: underline is /ˈʌndɚˌlaɪn/ while undermine is /ˌʌn.dəˈmaɪn/. Spoken aloud the problem disappears. In writing it persists, because they differ by a single letter - l in “underline” becomes m in “undermine”, and the parts of speech differ too (noun vs verb), which is usually the fastest check. Our composite confusion score for this pair is 42035, derived from the frequency rank of both members and their visual similarity.
underline is recorded at frequency rank #29,874, classified as anoun, pronounced /ˈʌndɚˌlaɪn/. undermine is at rank #12,161, tagged as averb, pronounced /ˌʌn.dəˈmaɪn/.
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 42035, this pair ranks #252,905 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of underline vs undermine
Shared letters: deinru. Private to "underline": l. Private to "undermine": m.
"underline" · 9 letters · shape VCCVCCVCV · "undermine" · 9 letters · shape VCCVCCVCV
Known mistypes of this pair
Frequently Asked Questions
Can "underline" and "undermine" be used interchangeably?
In ordinary English text, does "underline" or "undermine" show up more?
Useful next steps
Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.
- Full dictionary entry for "underline" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "undermine" - compare definitions side by side with the headword page. Word entry
- This pair ranks #252,905 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "underline" and "undermine" also get mixed up with nearby pairs, the highest-scored neighbour is "underline 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 #252,905 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.