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

With a short week to prepare for Thursday's game against the Jacksonville Jaguars at M&T Bank Stadium, Fagnano is expected to start, with Reed serving as his backup. — Cbs Baltimore, CBS News, 2 Nov. 2026

The Jaguars jumped on the Colts, scoring touchdowns on three of their first five possessions and opening up a 28-0 lead late in the second quarter thanks to backup safety Rayuan Lane’s 92-yard interception return. — ABC News, 2 Nov. 2026

Adjective

Which means there were backup quarterbacks more effective last season when throwing footballs to running backs. — Sam McDowell, Kansas City Star, 9 Nov. 2026

Javonte Williams finished with his second 100-yard game in three weeks (101 yards), while backup Tyler Goodson has firmly established himself in the offense with 77 yards on 12 carries. — Nick Harris, Fort Worth Star-Telegram, 9 Nov. 2026