Join Us On

An Encyclopædia Britannica Company

Spanish Central

Browse Dictionary Browse Thesaurus

Get our free apps!iPhone•iPad•Android

Word of the Day

Blog: Words at Play

Thesaurus

insure

verb

Synonyms and Antonyms of INSURE

to make sure, certain, or safe <took steps to insure the timely completion of the project>

Synonyms assure, cinch, guarantee, guaranty, ice, insure, secure

Related Words attest, certify, vouch, warrant, witness; pledge, promise, swear

Near Antonyms enfeeble, undermine, weaken

Learn More About

Dictionary: Definition of "insure"

Spanish Central: Spanish translation of "insure"

Nglish: Translation of "insure" for Spanish speakers

Browse

Seen & Heard

What made you want to look up insure? Please tell us where you read or heard it (including the quote, if possible).

View Seen & Heard Highlights from Around the Site

Test Your Vocabulary!

10 Charming Words for Nasty People

Put-downs with flair

When "Literally" isn't, well, literal

How to use a word that (literally) drives some people nuts.

Know what this is?

Test your vocab with our fun, fast game

Ailurophobia, and 9 other unusual fears

Join Us

Merriam-Webster
on Facebook

Merriam-Webster
on Twitter

Bookstore: Digital and Print

Merriam-Webster references for Mobile, Kindle, print, and more.

See All

Other Merriam-Webster Dictionaries

© Merriam-Webster, Incorporated