Synonyms of back (up)

back (up) 1 of 3

verb

1

as in to testify (to)

Related Words

• testify (to)
• bear out
• vouch (for)
• witness
• verify
• validate
• confirm
• corroborate
• vindicate
• certify
• authenticate
• argue
• support
• substantiate
• attest
• guarantee
• warrant
• affirm
• avouch
• prove
• assert
• aver
• document
• reinforce
• declare
• establish
• profess
• avow
• demonstrate

Dissimilar Words

• disprove
• refute
• contradict
• rebut
• deny
• challenge
• contest
• question
• dispute
• gainsay
• disavow
• disclaim

2

as in to gel

Related Words

• gel
• coagulate
• harden
• set
• congeal
• clot

Dissimilar Words

• flow
• run
• stream
• pour
• arise
• roll
• issue
• race
• course
• spring
• emanate
• disembogue
• rush
• effuse

backup

2 of 3

noun

ˈbak-ˌəp 

1

as in jam

a crowded mass (as of cars) that impedes or blocks movement

there was the inevitable backup of travelers trying to pass through airport security

Synonyms & Similar Words

• jam
• bottleneck
• congestion
• tailback
• snarl
• jam-up
• lock
• traffic
• logjam
• delay
• tangle
• tie-up
• stoppage
• gridlock
• slowdown
• crawl

2

as in replacement

a person or thing that takes the place of another

you didn't get the lead position, but you can be the backup to the chosen singer

Synonyms & Similar Words

• replacement
• substitute
• assistant
• surrogate
• reserve
• stand-in
• relief
• sub
• cover
• fill-in
• pinch hitter
• designated hitter
• proxy
• alternate
• locum tenens
• deputy
• delegate
• second
• agent
• makeshift
• attorney
• stopgap
• factor
• representative
• successor
• apology
• assignee
• rep
• understudy
• commissary
• envoy
• procurator
• reliever
• superseder

backup

3 of 3

adjective

as in makeshift

Related Words

• makeshift
• proxy
• substitute
• alternate
• stopgap
• make-do
• acting
• interim
• temporary
• provisional
• ad interim
• jackleg
• provisionary
• provisory

Dissimilar Words

• permanent
• long-term

Example Sentences

Recent Examples of back (up)

Noun

From there, the white flag was virtually raised by McVay on the sideline, sending out Stafford’s backup, Stetson Bennett, and other second-stringers to finish out the lopsided loss. — Scott Thompson Outkick, FOXNews.com, 11 Sep. 2026

Darian Mensah kept up his near-perfect start to the season, completing 14 of 15 passes for three touchdowns and no interceptions, but his backups were just as efficient. — Jordan McPherson, Miami Herald, 11 Sep. 2026

Adjective

Once Murray was off the field, veteran Carson Wentz, whom the Vikings kept on after serving in a backup role last season, was called upon to lead Minnesota for the remainder of the home opener. — Scott Thompson Outkick, FOXNews.com, 14 Sep. 2026

That’s how the Tokyo Foundation’s Masashi Kawai, speaking to The New York Times, described the reaction to Japan’s plan to name a backup capital, a designation that promises incentives such as hefty tax breaks. — Whitney Eulich, Christian Science Monitor, 14 Sep. 2026