1. criticize somebody or something harshly
stop running yourself down
When you ‘run someone down’ it can mean that you have been speaking about them in a critical or negative way. ‘Don’t run me down in front of our boss again.’ This is a phrase used in social and professional contexts.
2. hit somebody or something with a vehicle
the man was run down crossing the road
To ‘run someone down’ can mean to hit them with a vehicle, usually as a result or driving erratically. ‘My cat was found last night. He had been run down by a car.’ This is a term only used in specific circumstances to talk about car accidents.