fill in

fill someone in

to give someone information that they want or need. We filled her in on all the latest family news. I've asked Andy to fill in the marketing team about plans for the fall.

See also: fill

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fill in (for someone)

to do someone else's job temporarily. He discovered his love of acting when he filled in for a sick friend in a college play.

See also: fill

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fill in something

1. to give written answers to questions on a computer or on paper. Fill in the entire form and then click “submit.” If you have left out a date, first name, or other information, fill it in.

2. to complete a plan or idea. That's the basic idea, but we still have a lot of details to fill in.

See also: fill