1. Something that assures a particular outcome or condition: Lack of interest is a guarantee of failure.
a. A promise or assurance, especially one given in writing, that attests to the quality or durability of a product or service.
b. A pledge that something will be performed in a specified manner.
3. A guarantor.
4. A guaranty.
tr.v. guar·an·teed, guar·an·tee·ing, guar·an·tees
1. To assume responsibility for the debt, default, or miscarriage of.
2. To assume responsibility for the quality or performance of: guarantee a product.
3. To undertake to do, accomplish, or ensure (something) for another: guaranteed to free the captives; guarantees freedom of speech.
4. To make certain: The rain guarantees a good crop this year.
5. To guaranty.
6. To furnish security for.
7. To express or declare with conviction: I guarantee that you'll like this book.
[Alteration of Middle English garant, warranty, from Old French; see GUARANTY.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.