A crime is something that is particularly strictly forbidden. People find a crime worse than many other things that are not allowed. The worst crime is considered to be murder, that is, when you kill another person. Whoever commits a crime is called a criminal or a gangster.
What is forbidden is called a crime. The different offences are described in the law. Many crimes are only misdemeanours or administrative offences. One example is theft. For these offences in Germany, you have to pay a fine or go to prison for up to five years.
A felony, however, is an offence for which you go to prison for at least one year. A judge is not allowed to give a lesser sentence, because that is what the law says. Anyone charged with a crime must be defended by a lawyer.
Apart from murder, manslaughter is also a crime. It is the same as murder, but in murder the perpetrator also has particularly bad reasons for killing. For example, a criminal is also one who betrays his own country to enemies or wants to abolish his own government with a coup. Kidnappers, arsonists and robbers are also usually criminals.
Sometimes the term "crime" is used differently in everyday language. If someone flies a lot by plane, some people speak of a "crime against the environment". If someone wears a fancy dress, they speak of a "crime against good taste". However, these are not crimes in the sense of the law, but rather things that some people find very bad.