1. (noun)guarantee, warrant, warrantee, warranty a written assurance that some product or service will be provided or will meet certain specifications
2. (noun)guarantee an unconditional commitment that something will happen or that something is true "there is no guarantee that they are not lying"
3. (verb)guarantee, guaranty a collateral agreement to answer for the debt of another in case that person defaults
4. (verb)guarantee, vouch give surety or assume responsibility "I vouch for the quality of my products"
5. (verb)guarantee, ensure, insure, assure, secure make certain of "This nest egg will ensure a nice retirement for us"; "Preparation will guarantee success!"
6. (verb)undertake, guarantee promise to do or accomplish "guarantee to free the prisoners"
7. (verb)guarantee, warrant stand behind and guarantee the quality, accuracy, or condition of "The dealer warrants all the cars he sells"; "I warrant this information"
Definitions of 'guarantee'
Webster 1913 Dictionary
1. (noun)guarantee 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
2. (noun)guarantee one who binds himself to see an undertaking of another performed; a guarantor
3. (noun)guarantee the person to whom a guaranty is made; -- the correlative of guarantor
4. (noun)guarantee 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
Definition of guarantee 
