Guarantee

v. vouch for; give a guarantee; give a warranty; promise, assure

n. security; warranty; pledge; assurance

In commercial and consumer transactions, a warranty is an obligation that an article or service sold is as factually stated or legally implied by the seller, and that often provides for a specific remedy such as repair or replacement in the event the article or service fails to meet the warranty. A breach of warranty occurs when the promise is broken, i.e., a product is defective or not as should be expected by a reasonable buyer.
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Noun
1. a written assurance that some product or service will be provided or will meet certain specifications
(synonym) warrant, warrantee, warranty
(hypernym) assurance, pledge
(hyponym) security, surety
(derivation) warrant
2. a pledge that something will happen or that something is true; "there is no guarantee that they are not lying"
(hypernym) assurance, pledge
(hyponym) safety net
(derivation) warrant
3. a collateral agreement to answer for the debt of another in case that person defaults
(synonym) guaranty
(hypernym) collateral
Verb
1. give surety or assume responsibility; "I vouch for the quality of my products"
(synonym) vouch
(hypernym) pledge, plight
(hyponym) bail
(verb-group) ensure, insure, assure, secure
(derivation) warrant, warrantee, warranty
2. make certain of; "This nest egg will ensure a nice retirement for us"; "Preparation will guarantee success!"
(synonym) ensure, insure, assure, secure
(hyponym) doom
(verb-group) vouch
3. promise to do or accomplish; "guarantee to free the prisoners"
(synonym) undertake
(hypernym) promise, assure
(hyponym) underwrite, subvention, subvent
4. stand behind and guarantee the quality, accuracy, or condition of; "The dealer warrants all the cars he sells"; "I warrant this information"
(synonym) warrant
(hypernym) back, endorse, indorse, plump for, plunk for, support
(hyponym) cover, insure, underwrite

(n.)
The person to whom a guaranty is made; -- the correlative of guarantor.
  

(n.)
One who binds himself to see an undertaking of another performed; a guarantor.
  

(n.)
In law and common usage: to undertake or engage for the payment of (a debt) or the performance of (a duty) by another person; to undertake to secure (a possession, right, claim, etc.) to another against a specified contingency, or at all avents; to give a guarantee concerning; to engage, assure, or secure as a thing that may be depended on; to warrant; as, to guarantee the execution of a treaty.
  

(n.)
In law and common usage: A promise to answer for the payment of some debt, or the performance of some duty, in case of the failure of another person, who is, in the first instance, liable to such payment or performance; an engagement which secures or insures another against a contingency; a warranty; a security. Same as Guaranty.
  

The assumption of responsibility for payment of a debt or performance of some obligation if the liable party fails to perform to expectations.