If you click on the red x it will explain what it means.
Abuse Icon Question

I did, but it goes to the page explaining about abuse. I wanted to know why it was next to my opponents name. His user name is hotbrown3
Did this opponent do something against the policy?
I recently won a game by my opponent losing on time. I see a red icon with an "X" next to the user name and when a hover my mouse over it it says "closed abuse". What does that mean? Did I do something wrong?? Thanks...