The modern senses of this word are either the legal concept which arises from someone's having infringed a law; or the feeling of remorse and culpability which may not have anything to do with a legal or even social transgression. But in the Bible guilt is the result of a broken relationship between a person and God or one's neighbour, for which there is a personal or corporate responsibility.
There could be responsibility without actually knowing that a wrong action had been committed (Lev. 5: 17–19). In this area therefore it was possible for a great load of guilt to be accumulated, and a means of atonement and reconciliation was provided in the OT in the sacrificial system. Because of the Hebrew notion of corporate solidarity, it was possible for a whole group to be guilty of an individual's sin, as with Achan (Josh. 7)—a view repudiated by Ezekiel (33: 18–20).
In the NT Paul regards everybody, Jew and Gentile alike, as guilty before God (Rom. 1: 18–3: 20). That is why and how he can maintain that he ‘upholds the law’ (Rom. 3: 31). Christians may be deserving of punishment (1 Cor. 11: 27), but by the grace of God forgiveness is available.