Dictionary definition · guarantee
noun
- a written assurance that some product or service will be provided or will meet certain specifications
- an unconditional commitment that something will happen or that something is true"there is no guarantee that they are not lying"
- a collateral agreement to answer for the debt of another in case that person defaults
verb
- give surety or assume responsibility"I vouch for the quality of my products"
- make certain of"This nest egg will ensure a nice retirement for us"
- promise to do or accomplish"guarantee to free the prisoners"
- stand behind and guarantee the quality, accuracy, or condition of"The dealer warrants all the cars he sells"
Source: Open English WordNet (CC BY 4.0).