What is a unsportsmanlike conduct in football

An important condition in sport is a conscientious approach to an opponent throughout a match. What does unsportsmanlike conduct mean in football? This is boorish behavior towards rivals.

In fans’ slang, simulators are the worst. A judge may have a wrong decision, reducing the chances of winning. What is a unsportsmanlike conduct in soccer for the players? The essence of its meaning is decent behavior.