early 15c., from Old French infamie (14c.), earlier infame, and directly from Latin infamia "ill fame, bad repute, dishonor, from infamis "of ill fame," from in- "not, without" + fama "reputation" (see fame (n.)).
public disgrace or loss of reputation, particularly as a consequence of criminal conviction. In early common law, conviction for an infamous crime resulted in disqualification to testify as a witness. The criterion for considering a crime infamous was whether or not it stamped the offender as untrustworthy. The concept was, therefore, at first limited to so-called crimen falsi, originally perjury, but was extended to any crime involving fraud or corruption. Eventually, all felonies came to be treated as infamous. Testimonial incompetency for infamy, however, has been abolished by statute in England and generally in the United States as well.