犯罪又称为犯法，指做出触犯刑事法律规范的行为，不同于违反了民事、行政、纪律等法律规范，而在一般意义中，"犯罪"一词也可指侵犯其他同类个体（他人）或严重违背社会道德，而普遍不被社会容忍的行为。被裁定罪名成立的人即罪人或称罪犯，在中华人民共和国称为犯人或者犯罪分子或者犯罪嫌疑人，在****称为犯罪行为人、犯罪人或者行为人。研究犯罪的学科称为犯罪学。

依现代的刑法来看，犯罪没有一个简单又广为接受的定义，不过在法律中还是为了特定的因素而为犯罪下定义。

最通用的定义是犯罪是由法律定义出来的（若某事被适用的法律视为是犯罪，那就是犯罪）。另一种定义是犯罪是一种不止对其他个体有害，对群体或是国家也有害的行为，法律会订定禁止这様的事，并且会有订定罚则。

The term felony, in some common law countries, means a serious crime. The word originates from English common law (from the French medieval word "félonie"), where felonies were originally crimes that involved confiscation of a convicted person's land and goods. Other crimes were called misdemeanors. Many common law countries have now abolished the felony/misdemeanor distinction and replaced it with other distinctions, such as between indictable offences and summary offences. A felony is generally considered a crime of high seriousness, while a misdemeanor is not.