sure

1 of 2

adjective

ˈshu̇r 

ˈshər,

 especially Southern  ˈshȯr

surer; surest

1

a

: marked by or given to feelings of confident certainty

I'm sure I'm right

b

: characterized by a lack of wavering or hesitation

sure brush strokes

a sure hand

2

: admitting of no doubt : indisputable

spoke from sure knowledge

3

a

: bound, destined

is sure to win

b

: bound to happen : inevitable

sure disaster

4

: careful to remember, attend to, or find out something

be sure to lock the door

5

: firmly established : steadfast

a sure hold

6

: reliable, trustworthy

a sure friend

7

obsolete : safe from danger or harm

sureness noun

sure

2 of 2

adverb

: surely

Sure vs. Surely: Usage Guide

Most commentators consider the adverb sure to be something less than completely standard; surely is usually recommended as a substitute. Our current evidence shows, however, that sure and surely have become differentiated in use. Sure is used in much more informal contexts than surely. It is used as a simple intensive

I can never know how much I bored her, but, be certain, she sure amused me

—Norman Mailer

and, because it connotes strong affirmation, it is used when the speaker or writer expects to be agreed with.

it's a moot point whether politicians are less venal than in Twain's day. But they're sure as the devil more intrusive

—Alan Abelson

he sure gets them to play

—D. S. Looney

Surely, like sure, is used as a simple intensive

I surely don't want to leave the impression that I had an unhappy childhood

—E. C. Welsh

but it occurs in more formal contexts than sure. Unlike sure it may be used neutrally—the reader or hearer may or may not agree

it would surely be possible, within a few years, to program a computer to construct a grammar

—Noam Chomsky

and it is often used when the writer is trying to persuade.

surely a book on the avant-garde cannot be so conventional

—Karl Shapiro

Phrases

for sure

: without doubt or question : certainly

to be sure

: it must be acknowledged : admittedly

Synonyms

Adjective

• assured
• certain
• clear
• cocksure
• confident
• doubtless
• implicit
• positive
• sanguine

Adverb

• all right
• alright
• assuredly
• certainly
• clearly
• definitely
• doubtless
• easily
• forsooth
• hands down
• inarguably
• incontestably
• incontrovertibly
• indeed
• indisputably
• plainly
• really
• so
• surely
• truly
• unarguably
• undeniably
• undoubtedly
• unquestionably

Choose the Right Synonym for sure

sure, certain, positive, cocksure mean having no doubt or uncertainty.

sure usually stresses the subjective or intuitive feeling of assurance.

felt sure that I had forgotten something

certain may apply to a basing of a conclusion or conviction on definite grounds or indubitable evidence.

police are certain about the cause of the fire

positive intensifies sureness or certainty and may imply opinionated conviction or forceful expression of it.

I'm positive that's the person I saw

cocksure implies presumptuous or careless positiveness.

you're always so cocksure about everything

Examples of sure in a Sentence

Adjective

She's not sure who will be there.

Are you sure you want to go?

Are you sure about that?

She'll be there, I'm sure of it.

Are you sure of the results?

The return of the robins is a sure sign of spring.

The letter is a sure indication that she cares.

Pizza is a sure crowd pleaser.

The surest way to lose weight is with diet and exercise.

One sure way to improve your health is to stop smoking.

Adverb

we sure could use your help here

Recent Examples on the Web

Adjective

If Nintendo notices the same cryptographic signature on security certificates being used by hundreds of different consoles and accounts, for instance, the company can be relatively sure that all those users are engaging in piracy. —ArsTechnica, 17 June 2025

Assuming the keynote is on Sept. 10, or one day that week, the release date, as sure as eggs is eggs, will be the Friday of the following week: Friday, Sept. 19. —David Phelan, Forbes.com, 17 June 2025

Adverb

So sure, if Elon Musk wants to use his resources to do that, great. —Nbc News, NBC news, 8 June 2025

But a few more seven-inning starts sure would make a difference. —Abbey Mastracco, New York Daily News, 4 June 2025

Word History

Etymology

Adjective

Middle English seur, sure, from Anglo-French seur, from Latin securus secure

First Known Use

Adjective

13th century, in the meaning defined at sense 7

Adverb

14th century, in the meaning defined above

Phrases Containing sure

• a good/safe/sure bet
• (as) sure as I'm standing here
• a sure thing
• be sure
• good/safe/sure bet
• make sure
• one thing is (for) sure
• sure as hell
• sure bet
• sure enough
• sure-footed
• sure-handed
• sure of oneself
• sure thing
• yeah, sure

Rhymes for sure

• boor
• cour
• cure
• jure
• lure
• moor
• pure
• spoor
• tour
• abjure
• adjure
• allure

Kids Definition

sure

1 of 2 adjective

ˈshu̇(ə)r 

 especially Southern  ˈshō(ə)r

1

: firmly established : steadfast

a sure hold

2

: reliable, trustworthy

a sure friend

3

: having no doubt : confident

I'm sure I'm right

4

: not to be doubted : certain

sure evidence

5

a

: bound to happen : inevitable

sure disaster

b

: bound as if by fate

we are sure to win

sureness noun

sure

2 of 2 adverb

1

: surely sense 1b

2

: surely sense 2

Etymology

Adjective

Middle English seur, sure "safe from danger or harm," from early French seur (same meaning), from securus "secure" — related to secure