# certain vs certainly

> English confusable word pair

## The two words

### certain
*adjective · IPA /ˈsɜː.tən/ · frequency rank #707*
Sure in one's mind, positive; absolutely confident in the truth of something.

### certainly
*adverb · IPA /ˈsɜː.tn̩.li/ · frequency rank #1,069*
In a way which is certain; with certainty.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/vs/certain-vs-certainly