To strongly and solemnly refuse to own or acknowledge; to deny responsibility for, approbation of, and the like.
To deny; to show the contrary of; to deny legitimacy or achievement of any kind.
To assume or take responsibility for a debt or other obligation.
To make something certain.
To give an assurance that something will be done right.
The person to whom a guarantee is made.
A person who gives such a guarantee; a guarantor.
A legal assurance of something, e.g. a security for the fulfillment of an obligation.
More specifically, a written declaration that a certain product will be fit for a purpose and work correctly; a warranty
Anything that assures a certain outcome.