guarantee

Etymology

From Old French guarantie (perhaps via a later Spanish garante), from the verb guarantir (“to protect, assure, vouch for”), ultimately from Old Frankish *warjand, *warand (“a warrant”), or from guaranty. Doublet of guaranty and warranty.

noun

1. Anything that assures a certain outcome.
   Can you give me a guarantee that he will be fit for the match?
2. A legal assurance of something, e.g. a security for the fulfillment of an obligation.
3. More specifically, a written declaration that a certain product will be fit for a purpose and work correctly; a warranty
   The cooker comes with a five-year guarantee.
4. The person to whom a guarantee is made.
5. (colloquial) A person who gives such a guarantee; a guarantor.

verb

1. To give an assurance that something will be done right.
2. To assume or take responsibility for a debt or other obligation.
3. To make something certain.
   The long sunny days guarantee a good crop.