Which to use
“underline” is a noun and “underpin” is a verb - they look or sound alike but fill different roles in a sentence.
- #29,874
- “underline” frequency rank
- #43,448
- “underpin” frequency rank
- 73322
- confusion score
Side-by-Side Comparison
| Feature | underline | underpin |
|---|---|---|
| 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 support from below with props or masonry. |
Where the spellings diverge
Shared letters are muted; the letters that actually set underline and underpin apart are highlighted. They share 7 letters in sequence, which is exactly why the eye skips the difference.
Spelling & Dictionary Insight
These two trip readers on the page rather than in the ear: underline is /ˈʌndɚˌlaɪn/ while underpin is /ˌʌn.dəˈpɪn/. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 letter(s) in length, and the parts of speech differ too (noun vs verb), which is usually the fastest check. Our composite confusion score for this pair is 73322, 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/. underpin is at rank #43,448, tagged as averb, pronounced /ˌʌn.dəˈpɪn/.
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 73322, this pair ranks #40,028 of 530,003 scored English confusable pairs - among the most confusable pairs.
Orthographic DNA of underline vs underpin
Shared letters: deinru. Private to "underline": l. Private to "underpin": p.
"underline" · 9 letters · shape VCCVCCVCV · "underpin" · 8 letters · shape VCCVCCVC
Known mistypes of this pair
Frequency comparison
Frequently Asked Questions
Can "underline" and "underpin" be used interchangeably?
Which is more common, "underline" or "underpin"?
Remembering underline vs underpin
The fastest way to pick the right one every time.
- Check the role first: if you need a noun, it's “underline”; for a verb, it's “underpin”.
- See each word in full, definition, IPA, etymology and its other confusables. Full “underline” entry
- Browse more pairs most likely to be confused. Most confusable