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Dictionary.com
Definitions

back up

VERB
move backward
Synonyms
STRONGEST
fall back retreat
WEAK
abandon withdraw
Antonyms
STRONGEST
forge ahead
WEAK
continue defend pursue
VERB
support
Synonyms
WEAK
advance back champion confirm encourage help lend support promote pull for stand behind stand by
Antonyms
WEAK
continue defend pursue
ADJECTIVE
substitute
Synonyms
STRONG
alternate alternative another stand-in

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

And even if the war ends soon, it will take some time for the regional infrastructure to get back up to speed, and for damaged facilities to be rebuilt.

From MarketWatch • May 3, 2026

But right now "there is not the clinical evidence to back up the wild claims being made by the industry", says Prof Ahmed.

From BBC • May 2, 2026

Mexico is seeking "irrefutable" evidence to back up the shock US drug trafficking charges against a sitting governor and other officials before proceeding with extradition requests, President Claudia Sheinbaum said Thursday.

From Barron's • Apr. 30, 2026

To back up: State legislatures oversee the drawing of their electoral maps into districts.

From Slate • Apr. 29, 2026

Today, after he had finished his oatmeal, he went back up to his bedroom to look around.

From "All About Sam" by Lois Lowry