certainly

adverb

cer·​tain·​ly ˈsər-tᵊn-lē 

1

: in a manner that is certain : with certainty

2

: it is certain that : assuredly

Synonyms

• definitely
• surely
• sure
• clearly
• probably
• really

Examples of certainly in a Sentence

It will certainly rain tomorrow.

This year's festival was certainly much better than last year's.

I'm certainly going to try.

The new version is most certainly easier to use.

The snake that bit her was almost certainly poisonous.

Recent Examples on the Web

Russia is certainly a threat to the United States and its European allies in NATO — but European nations can and should take the lead for the conventional defense of Europe, given that their population is five times and their economy is 10 times that of Russia. —Morgan Chalfant, semafor.com, 28 July 2025

The heat was certainly a factor for the audience, which brought handheld folding fans and tried to stay hydrated in the near 100-degree temperatures. —Courtney Devores, Charlotte Observer, 28 July 2025

There certainly will be future periods when more diversified portfolios of contemporary plans underperform, whether due to a recession or other unforeseen economic event. —Dan Doonan, Forbes.com, 28 July 2025

Winston could certainly be a target for teams in those positions, but one Giants insider suggests the veteran is unlikely to leave the building without a massive offer going to the Giants. —Justin Grasso, MSNBC Newsweek, 28 July 2025

Word History

First Known Use

14th century, in the meaning defined at sense 1

Phrases Containing certainly

• certainly not

Rhymes for certainly

• uncertainly

Kids Definition

certainly

adverb

cer·​tain·​ly ˈsərt-ᵊn-lē 

1

: in a manner that is certain : for certain

the only event of which anything is certainly known

2

: without doubt : surely

certainly you can do it