The word felonious means to have the air of a felony or to have the air of evil. A felonious act is one in which a felony is carried out. Examples include rape, murder, robbery, or pedophilia. In order for something to be felonious it has to have the nature of a felony. Any brute force used against a person or duress caused which resulted in financial gain would also be considered felonious.
The intent must be present to commit a serious crime for an action to be felonious, this is the bar to which situations are measured in all circumstances when deciding whether something was done on purpose or unintentionally. If something is done unintentionally it would result in the lowest type of felonious occurrence.