fill-in

1 of 2

noun

ˈfil-ˌin 

: someone or something that fills in

fill in

2 of 2

verb

filled in; filling in; fills in

transitive verb

1

: to enrich (something, such as a design) with detail

2

: to give necessary or recently acquired information to

I'll fill you in

intransitive verb

: to fill a vacancy usually temporarily

interns filled in for regular staffers

Synonyms

Noun

• substitute
• replacement
• backup

Verb

• inform
• tell
• advise
• catch up

Examples of fill-in in a Sentence

Noun

I'm just a fill-in, so I have no idea where office supplies are kept

Verb

my friend quickly filled me in on the portion of the movie that I had missed

she's only filling in while the regular secretary is on vacation

Recent Examples on the Web

Noun

How many of us willingly fill-in surveys, even when they are described as legally required? —Vipin Bharathan, Forbes.com, 31 Aug. 2025

Strictly speaking, the result was derivative, fill-in-the-blank. —Joshua Rothman, New Yorker, 25 Aug. 2025

Verb

When a small job of filling in a hole that a pet has dug or where a root has rotted, homeowners can easily handle this type of job themselves. —Rebecca Jones, Southern Living, 11 Sep. 2025

Students could then be assigned a diagram of the water cycle with missing labels; filling in the blanks on the diagram offers them a hands-on activity to reinforce the information in the quiz. —Hannah Nwoko, Parents, 10 Sep. 2025

Word History

First Known Use

Noun

1917, in the meaning defined above

Verb

1840, in the meaning defined at transitive sense 1

Rhymes for fill-in

• akin
• auxin
• buckskin
• chagrin
• deerskin
• foreskin
• fuchsin
• herein
• kingpin
• linchpin
• pigskin
• pinyin

Kids Definition

fill in

verb

1

: to furnish with specified information

fill in an application

filled us in on the latest news

2

: to fill a vacancy usually temporarily : substitute

filled in during the emergency