1 A2 neutral
To write information in the blank spaces of a form or document.
"Please fill in your name and address at the top of the application form."
separable
fill in
B1 neutral separable transitive/intransitive
To complete missing information on a form, to substitute for someone temporarily, or to inform someone of facts they missed.
In plain English
To write missing information somewhere, do someone's job for a short time, or tell someone what they missed.
What does "fill in" mean?
4 meanings, ordered from most common to least. Color-coded by CEFR level.
2 B1 informal
To do someone else's job or take their place temporarily while they are away.
"My colleague is on holiday, so I'm filling in for her this week."
inseparable
3 B1 idiomatic informal
To tell someone the details or news they have missed about a situation.
"I missed the first part of the meeting — can you fill me in later?"
separable
4 A2 neutral
To colour in or shade an outlined area in a drawing or diagram.
"The children were asked to fill in the outline of the map with different colours."
separable
Literal vs figurative
Words literally mean
To put something in a gap or empty space to fill it.
Actually means
To write missing information somewhere, do someone's job for a short time, or tell someone what they missed.
Usage tip
Sense 1 (completing forms) is more common in British English; Americans more often say 'fill out'. Sense 2 (substituting) is informal. Sense 3 (informing) is informal and commonly used with 'on': 'fill me in on what happened'.
Words that pair with "fill in"
Natural word combinations native speakers use most often.
form blanks details colleague gaps time
How to conjugate "fill in"
The five tense forms you'll use most often.
Base
fill in
I/you/we/they
3rd person
fills in
he/she/it
Past simple
filled in
yesterday
Past participle
filled in
have + pp
-ing form
filling in
continuous
Hear "fill in" in the wild
Listen to native speakers using "fill in" in real YouTube videos — click a clip to watch it on Looplines.
Keep exploring
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