What is concept of Route Poisoning? Please explain?

Route Poisoning : It means removing a specific route from routers when that specific route is down or it's not reachable

In case of Rip : When a Route ( ex 1.1.1.1/32 ) is down it removes that route from it's routing table and send a triggered update as network = 1.1.1.1 as metric 16. which makes this route as poison. when a router recieves a route as metric 16 it just remove that route immediately.