False Positive

(f ls poz &-tiv) (n.) The condition in which spam-filtering software will incorrectly identify a legitimate, solicited or expected e-mail as a spam transmission. As spammers use more and more sophisticated methods of averting spam filters, the filters have to adapt to keep the onslaught of spam at bay. While sophisticated spam filters, such as the ones that use Bayesian filtering, are keeping out the overwhelming majority of spam e-mails, some spam still slips past the filters, and unfortunately some legitimate e-mail is incorrectly identified as spam and filtered out.