Meaning
fill A in on B means to provide someone (A) with information or details about something (B). It is commonly used when one person updates another about a situation, plan, or event they missed.
Grammar and Usage
- Structure: fill + [person] + in on + [topic/event]
 - Verb type: Phrasal verb, transitive, separable (but usually kept together).
 
Examples of structure:
- "fill me in on the details"
 - "fill her in on what happened yesterday"
 
Common Phrases
- fill someone in on the details
 - fill me in on what happened
 - fill her in on the plan
 - fill them in on the meeting
 
Collocations
- fill someone in on + the details / the news / the plan / the situation / the meeting / what happened
 
Examples
- Can you fill me in on what I missed in class yesterday?
 - I need to fill her in on the changes before the meeting.
 - He filled us in on his travel experiences in Europe.
 - Please fill me in on the latest company news.
 - She filled her friend in on the gossip from the party.
 - I’ll fill you in on the details later.
 - The manager filled the team in on the new project.
 - Can you fill him in on the current situation?
 
Synonyms or Related
- update someone on
 - brief someone about
 - inform someone of
 - bring someone up to speed
 
Antonym
- keep someone in the dark
 - withhold information from someone
 
