guarantee

American  

[gar-uhn-tee] / ˌgær ənˈti /

noun

1. a promise or assurance, especially one in writing, that something is of specified quality, content, benefit, etc., or that it will perform satisfactorily for a given length of time.

   a money-back guarantee.

2. an assurance that another’s obligation will be fulfilled, or something presented as such security; guaranty.

3. something that assures a particular outcome or condition.

   Wealth is no guarantee of happiness.

4. a person who gives a guarantee or guaranty; guarantor.

5. a person to whom a guarantee is made.

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verb (used with object)

guaranteed, guaranteeing

1. to secure, as by giving or taking security.

   A credit card guarantees your reservation at the hotel.

2. to make oneself answerable for (something) on behalf of someone else who is primarily responsible.

   to guarantee the fulfillment of a contract.

3. to undertake to ensure for another, as rights or possessions.

   The Constitution guarantees freedom of religion.

4. to serve as a warrant or guaranty for.

5. to undertake to protect or indemnify.

   to guarantee a person against loss.

6. to undertake (to do something).

   I will guarantee to prove every word I stated.

7. to promise (usually followed by a clause as object).

   I guarantee that I'll be there.

guarantee British  

/ ˌɡærənˈtiː /

noun

1. a formal assurance, esp in writing, that a product, service, etc, will meet certain standards or specifications

2. law a promise, esp a collateral agreement, to answer for the debt, default, or miscarriage of another

3. 1. a person, company, etc, to whom a guarantee is made

   2. a person, company, etc, who gives a guarantee

4. a person who acts as a guarantor

5. something that makes a specified condition or outcome certain

6. a variant spelling of guaranty

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verb

1. (also tr) to take responsibility for (someone else's debts, obligations, etc)

2. to serve as a guarantee for

3. to secure or furnish security for

   a small deposit will guarantee any dress

4. to undertake to protect or keep secure, as against injury, loss, etc

5. to ensure

   good planning will guarantee success

6. (may take a clause as object or an infinitive) to promise or make certain

Usage

What does guarantee mean? A guarantee is a promise or assurance, especially one that is written or legally binding, that something is of a stated quality or will perform as stated, such as a guarantee that a car you purchase will operate correctly. A guarantee is also an assurance of a particular outcome or condition, as in Weather predictions are not guarantees. Weather often changes quickly. To guarantee something is to secure something, as a ticket guarantees entry to a movie showing. As well, to guarantee is to promise to do something, usually by signing a legally binding agreement, as in The company guaranteed me a job when I signed the contract. Example: I guarantee you will love your purchase and will give you a full refund if you don’t.

Other Word Forms

• nonguarantee
  noun
• preguarantee
  noun
• quasi-guaranteed
  adjective
• reguarantee
  noun
• superguarantee
  noun
• unguaranteed
  adjective

Etymology

Origin of guarantee

First recorded in 1670–80; alteration of guaranty

Explanation

To guarantee is to promise or to a make binding agreement. If a baseball player guarantees his team will win the World Series, he better not lead the league in strikeouts. Guarantee is a word that is both a noun and a verb: the noun means "a binding agreement" and the verb is the act of making that agreement. This word seems to have come from garante, the Spanish word for "protect" and it's related to the Old French word warrant, which means "to authorize." Today, we often come across guarantee in advertisements, and you might wonder how they might guarantee to make your social life better if your teeth are whiter!

Example Sentences

OpenAI’s app developer terms don’t guarantee discoverability, but the company said it is experimenting with ways to surface apps more directly within conversations, without explicit invocation.

From The Wall Street Journal • May 7, 2026

Of course, having the best defence is not a guarantee of success in the Champions League.

From BBC • May 6, 2026

Patients are asked to arrive early to check in for the convenience of providers, but this is no guarantee they will be seen on time.

From MarketWatch • May 1, 2026

Turk urged Cambodia to ensure that legitimate criticism and expression are protected rather than criminalised, to safeguard civic space, to guarantee the independence of the judiciary and uphold fair trial guarantees.

From Barron's • May 1, 2026

They quoted the First Amendment guarantee of “the right of the people peacefully to assemble, and to petition the Government for a redress of grievances.”

From "Votes for Women!" by Winifred Conkling

Related Words

• agreement
• assurance
• certificate
• collateral
• contract
• deposit
• insurance
• security
• warranty