What is slashing?

I came across this technical word and I thought noobs like me would get interested. Here is what I found. (source Staking · Polkadot Wiki) (Centrifuge Chain Validator Guide - HackMD) and I applied it to RAD token:

Slashing will happen if a validator misbehaves in the network. They and their nominators will get slashed by losing a percentage of their staked RAD. Validators must stay online and available with very high up-time. They will be held responsible and incur slashing penalties for deliberate attacks (e.g. attacks the network) running modified software, severe bugs in the code, and unresponsiveness,(e.g. goes offline)

Now what happens with the slashed RAD?