Having the quality of felony; malignant; malicious; villainous; traitorous; perfidious; in a legal sense, done with intent to commit a crime; as, felonious homicide.

involving or being or having the nature of a crime; "a criminal offense"; "criminal abuse"; "felonious intent"

Describing an offense which is done with malicious, villainous criminal intent. IE: felonious assault. Felony A serious offense carrying a penalty of incarceration from one year to life in a state prison, to the death penalty.