Option for block/report

It doesn´t happen often but every now and then theres a toxic and verbally abusing player in a game, spouting insults and profanities against other players. Be it from losing a game or plainly disagreeing with others.
This is not something I enjoy, at all, and would appreciate an option to block that person so I never get matched with someone so foul again.
If there already exists such an option please tell me how to do it.