Definition of "guarantee"

guarantee

/ˌɡæɹənˈtiː/

noun
plural guarantees
1. Anything that assures a certain outcome.
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
4. The person to whom a guarantee is made.
5. (colloquial) A person who gives such a guarantee; a guarantor.
  Quotations
  But God who is the great Guarantee for the Peace , Order , and good behaviour of Mankind
  1692–1717, Robert South, Twelve Sermons Preached upon Several Occasions, 6th edition, volumes (please specify |volume=I to VI), London: […] J[ames] Bettenham, for Jonah Bowyer, […], published 1727
verb
third-person singular simple present guarantees, present participle guaranteeing, simple past and past participle guaranteed
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.