irregularvsirregularlyConfusable pair

Quick tell: irregular is a adjective, irregularly is an adverb, so they fill different roles in a sentence.

Which to use

“irregular” is an adjective and “irregularly” is an adverb - they look or sound alike but fill different roles in a sentence.

#11,238
“irregular” frequency rank
#34,548
“irregularly” frequency rank
45786
confusion score

Side-by-Side Comparison

Feature irregular irregularly
Definition Nonstandard; not conforming to rules or expectations. In an irregular manner; without rule, method, or order.

Where the eye mixes irregular and irregularly

Muted = shared; highlighted = the visual trap. They share 9 letters in sequence.

9 ch
irregular
11 ch
irregularly

Why the eye confuses irregular with irregularly

These two trip readers on the page rather than in the ear: irregular is /ɪˈɹɛɡ.jʊ.lə/ while irregularly is /ɪˈɹɛɡjʊləli/. Spoken aloud the problem disappears. In writing it persists, because they differ by 2 extra letter(s) - “irregular” sits inside “irregularly”, and the parts of speech differ too (adjective vs adverb), which is usually the fastest check. Our composite confusion score for this pair is 45786, derived from the frequency rank of both members and their visual similarity.

irregular is recorded at frequency rank #11,238, classified as anadj, pronounced /ɪˈɹɛɡ.jʊ.lə/. irregularly is at rank #34,548, tagged as anadv, pronounced /ɪˈɹɛɡjʊləli/.

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 45786, this pair ranks #217,922 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of irregular vs irregularly

Shared letters: aegilru. Private to "irregular": -. Private to "irregularly": y.

"irregular" · 9 letters · shape VCCVCVCVC  ·  "irregularly" · 11 letters · shape VCCVCVCVCCV

Known mistypes of this pair

  • irregulariregular · irergular · irreggular · irregluar · irregualr · irregularr · irregullar · irregulra
  • irregularlyiregularly · irergularly · irreggularly · irregluarly · irregualrly · irregulalry · irregularlly · irregularlyy

Frequently Asked Questions

Can "irregular" and "irregularly" be used interchangeably?
No - they are not even the same part of speech. "irregular" is an adjective and "irregularly" an adverb, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "irregular" or "irregularly"?
"irregular" is the more common of the two: it sits at frequency rank #11,238 in our English list, against #34,548 for "irregularly". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

Eye-level mix-up between "irregular" and "irregularly" is sorted above. Next: full entries or other pairs that share a letter shape.

  • Full dictionary entry for "irregular" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "irregularly" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #217,922 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "irregular" and "irregularly" also get mixed up with nearby pairs, the highest-scored neighbour is "irregularity vs irregularly". 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 #217,922 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