[darreninthenet]

That depends on the country... speeding in the UK, for example, absolutely is a criminal offence.

In fact, in the UK, apart from a tiny number of civil matters used in criminal law, breaking the law (ie doing something illegal) is always a criminal offence.

[judge2020]

dragonwriter and others here are both right. In terms of language, the terms are the same, in that you are a criminal if you violate the law. However, in many countries and regions "criminal" can be a way to discern that certain crimes come with specific punishments, like jail time or personal fines.

For example, in the US there's criminal and civil cases. You can't be incarcerated for losing a civil suit, unless you don't pay whatever judgement the court discerns (which is considered criminal contempt of court).

In the US the difference also comes into play in terms of who can bring certain charges against you. If you were to sue someone, you can't sue them for assault and battery or homicide, because these are considered criminal charges and only the District Attorney / the government can bring these charges against someone. In this case, there are typically parallel civil remedies you can sue for, such as "wrongful death" and "emotional distress" which is strictly to recuperate financial loss.