fill in

present singular third person fills in · participle present filling in · participle past filled in · past filled in

1. idiomatictransitiveTo fill; to replace material that is absent or has been removed.

   After you're done laying the pipe, fill in the trench.

   2 more examples

   The decking of the bridge consisted of steel troughing over an average clear span of 26 ft., the troughing being filled in with concrete to form the road surface.

   1958 May 28, “Widening at Dun Laoghaire, C.I.E.”, in Railway Magazine, page 342

   Typically for the 'get-on-with-it' era, the railway and military worked like demons to restore the vital rail link. The crater was rapidly filled in and the earth tamped solid, the wreckage was removed by breakdown trains, new rails and sleepers were rushed forward by willing hands, and US Army bulldozers piled in. By 2020 on the same day, both tracks were open for traffic again where there had been a gaping pit just hours before.

   2022 January 12, Benedict le Vay, “The heroes of Soham...”, in RAIL, number 948, page 43

2. idiomatictransitiveTo inform somebody, especially to supply someone missing or missed information.

   If you know anything about this, maybe you can fill me in.

   1 more example

   Wait, uh - I-I-I should go distract Caine so he doesn't l-listen in on this. Uh, j-just fill me in afterwards.

   2026 March 20, Gooseworx, “hjsakldfhl” (20:32 from the start), in The Amazing Digital Circus, episode 8, spoken by Jax (Michael Kovach)

3. idiomaticintransitiveTo substitute for somebody or something.

   He can't go on vacation very often because there is nobody to fill in for him.

   1 more example

   By 6 am, Jodi hadn’t arrived yet, and Kuns filled in for her after a second call went unanswered.

   2026 August 10, Nicholas Muhoro, “Jodi Huisentruit, 27, Vanished From Her Apartment Parking Lot in 1995. Police Found Signs of a Struggle”, in Skip Boring, archived from the original on 11 Aug 2026

4. UKidiomatictransitiveTo complete a form or questionnaire with requested information.

   I've got a form that is to be filled in in ink.

   1 more example

   The findings emerged from questionnaires filled in by 2,211 staff in 145 wards of 55 hospitals in England and Wales and 105 observations of care of dementia patients. Two-thirds of staff said they had not had enough training to provide proper care, 50% said they had not been trained how to communicate properly with such patients and 54% had not been told how to handle challenging or aggressive behaviour.

   2011 December 16, Denis Campbell, “Hospital staff 'lack skills to cope with dementia patients'”, in Guardian

   Synonyms: fill out

5. idiomaticslangTo beat up; to physically assault.

   Talk to me like that again and I'll fill you in!

   1 more example

   It's just a rumour that was spread around town Somebody said that someone got filled in For saying that people get killed in The result of this shipbuilding

   1982, Elvis Costello, Shipbuilding