1) Criminal 2) Illegal 
• (a.) Having the quality of felony; malignant; malicious; villainous; traitorous; perfidious; in a legal sense, done with intent to commit a crime; as, felonious homicide.
adj. An act performed with criminal intent. Used to differentiate between a malicious wrong and an intentional crime.
Fe·lo'ni·ous adjective Having the quality of felony; malignant; malicious; villainous; traitorous; perfidious; in a legal sense, done with intent to commit a crime; as, felonious homicide. « O thievish Night, Why should'st thou, but for some felonious end, In thy dark lantern thus ...