impossiblevsimpossiblyTell them apart

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

Which to use

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

#1,724
“impossible” frequency rank
#30,091
“impossibly” frequency rank
31815
confusion score

Side-by-Side Comparison

Feature impossible impossibly
Definition Not possible; not able to be done or happen. Not possibly; in an impossible manner.

Letter map: impossible vs impossibly

Shared letters muted; letters that set impossible and impossibly apart highlighted. Shared run: 9.

10 ch
impossible
10 ch
impossibly

Grammar separator: impossible vs impossibly

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: impossible is anadjective and impossiblyanadverb. On the page they differ by a single letter - e in “impossible” becomes y in “impossibly”. Our composite confusion score for this pair is 31815, derived from the frequency rank of both members and their visual similarity.

impossible is recorded at frequency rank #1,724, classified as anadj, pronounced /ɪmˈpɒs.ɪ.bəl/. impossibly is at rank #30,091, tagged as anadv.

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 31815, this pair ranks #342,958 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of impossible vs impossibly

Shared letters: bilmops. Private to "impossible": e. Private to "impossibly": y.

"impossible" · 10 letters · shape VCCVCCVCCV  ·  "impossibly" · 10 letters · shape VCCVCCVCCV

Known mistypes of this pair

  • impossibleimmpossible · imopssible · imposible · imposisble · impossable · impossbile · impossibble · impossibel
  • impossiblyimmpossibly · imopssibly · imposibly · imposisbly · impossbily · impossibbly · impossiblly · impossiblyy

Frequently Asked Questions

Do "impossible" and "impossibly" mean the same thing in a sentence?
No - they are not even the same part of speech. "impossible" is an adjective and "impossibly" an adverb, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "impossible" or "impossibly"?
"impossible" is the more common of the two: it sits at frequency rank #1,724 in our English list, against #30,091 for "impossibly". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

After this comparison

Done with this confusable. These links stay specific to "impossible" and "impossibly".

  • Full dictionary entry for "impossible" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "impossibly" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #342,958 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "impossible" and "impossibly" also get mixed up with nearby pairs, the highest-scored neighbour is "impassable vs impossible". 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 #342,958 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