warranty
/ˈwɒrəntɪ/noun
(pl. -ies)
1- a written guarantee, issued to the purchaser of an article by its manufacturer, promising to repair or replace it if necessary within a specified period of time（商品）保单, 保用书, 保修单：
the car comes with a three-year warranty
该车有三年的保用期
mass noun as your machine is under warranty, I suggest getting it checked.你的机器仍在保用期内, 所以我建议把它送去检查一下。
1.1
- (in an insurance contract) an engagement by the insured party that certain statements are true or that certain conditions shall be fulfilled, the breach of it invalidating the policy（保险合同用语）（被保险人对某些陈述所作的）保证, 担保。
1.2
- mass noun [usu. with negative] archaic justification or grounds for an action or belief〈古〉正当理由; 依据：
you have no warranty for such an audacious doctrine.
对于这样大胆的学说, 你缺乏相应的依据。
词源
Middle English: from Anglo-Norman French warantie, variant of garantie （see GUARANTY）. Early use was as a legal term denoting a covenant annexed to a conveyance of property， in which the vendor affirmed the security of the title.