certainly

/ˈsɜː.tn̩.li/

//ˈsɜː.tn̩.li// adv

By · According to Wiktionary data (CC BY-SA) ·

"certainly" is a 9-letter English headword indexed on PlainSpell.

The verdict

“certainly” is a regularly-used English word, ranked #1,069 in English word frequency and used as an adverb.

#1,069
frequency rank, English
9
letters
14
tracked misspellings
2
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - In a way which is certain; with certainty.

Visual similarity to commonly confused words

How many letter changes separate each confused pair (Levenshtein distance, normalized).

certainly vs certainty
89% similar
certainly vs certain
78% similar

Source: PlainSpell confusable corpus (Wiktionary, CC BY-SA).

Key facts for certainly
PropertyValue
Headwordcertainly
LanguageEnglish
Part of speechAdverb
IPA/ˈsɜː.tn̩.li/
Letters9
Frequency rank#1,069
Misspellings tracked14
Confusable pairs2
SourceWiktionary (kaikki.org)

Where “certainly” sits in English frequency

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right). certainly lands here:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Source: FrequencyWords open word-frequency list.

Spelling & Dictionary Insight

The English entry for certainly is 9 letters long, classified as an adverb, and transcribed in the International Phonetic Alphabet as /ˈsɜː.tn̩.li/. Corpus data places it at rank #1,069 in overall English word frequency, indicating it appears regularly in written and spoken text. Wiktionary records 3 distinct senses for this headword, so context determines which meaning a reader should apply.

Our generated misspelling index lists 14 likely wrong-spelling variants for certainly, with forms such as "ccertainly", "ceratinly", and "cerrtainly". Each of these forms differs from the correct spelling by one small edit: a doubled letter, a dropped silent letter, or a substituted vowel. It also participates in 2 confusable-pair relationships, "certainty", "certain", since the words sound or look close enough that writers reach for the wrong one mid-sentence.

Etymologically, the entry records: From Middle English certeynly; equivalent to certain + -ly. The correct English form is certainly, spelled C-E-R-T-A-I-N-L-Y.

Definition

  1. 1
    In a way which is certain; with certainty.
  2. 2
    Without doubt, surely.
  3. 3
    An emphatic affirmative answer; of course.

Etymology

From Middle English certeynly; equivalent to certain + -ly.

Synonyms

absolutelybeyond doubtindubitablysure thingundoubtedlywiswithout a doubtdefinitelydoubtlesslyin factindeedindisputablyindubitablyno doubtreallysuresurelytrulyundoubtedlyunquestionablywiswithout a doubtrightlydamn rightdamn straightfo shizzlefor sureoh yeahwye ayeassuredlycertainlycategoricallydecisivelydoubtlessex faciefor a factfor certainpositivelyquestionlesslyself-evidentlyunarguablyundeniablyunconditionallyundoubtablyunivocallywithout doubtwithout question

Antonyms

arguablyconditionallydebatablydeniablydoubtfullyquestionablyuncertainly

This word in other languages

ciertamente(Español)certainement(Français)sicherlich(Deutsch)certamente(Português)

Common misspellings

Also misspelled as: ccertainly,ceratinly,cerrtainly,certailny,certainlly,certainlyy,certainnly,certainyl,certanily,certianly,certtainly,cetrainly,cretainly,ecrtainly

Misspelling Pattern Breakdown

How far each generated variant is from the correct spelling of certainly - measured in single-character edits (insert, delete, or substitute a letter). Larger bars are easier to catch; one-edit slips are the sneakiest.

ccertainly1ceratinly2cerrtainly1certailny2certainlly1certainlyy1certainnly1certainyl2
Edit distance from "certainly"

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "certainly"?
"certainly" is spelled C-E-R-T-A-I-N-L-Y. The IPA pronunciation is /ˈsɜː.tn̩.li/.
What does "certainly" mean?
As an adverb, "certainly" means: In a way which is certain; with certainty.
What words are commonly confused with "certainly"?
"certainly" is commonly confused with "certainty", "certain". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
How do you pronounce "certainly"?
The IPA (International Phonetic Alphabet) transcription for "certainly" is /ˈsɜː.tn̩.li/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "certainly"?
From Middle English certeynly; equivalent to certain + -ly. See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Using “certainly”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is C-E-R-T-A-I-N-L-Y - every other letter order is a misspelling in standard orthography.
  • Say it as /ˈsɜː.tn̩.li/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Don't mix it up with “certainty” - see the side-by-side comparison. certainly vs certainty
  • Browse more English words and confusable pairs in the same reference. English words
Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list FrequencyWords open word-frequency list