n. A pathological social condition in which rumor and innuendo are passed off as facts.
Palmer-Tomkinson also has been reported to be horsing around with the heir to the throne, Prince William, 17, and tongues are wagging. Saying she is a victim of "rumortism," Palmer-Tomkinson denied suggestions that the prince is anything but a 'mate' to her (that's mate in the British sense).
—Kris Banvard, “A Fun Time Was Had By All,” The Columbus Dispatch, October 14, 1999
1999 (earliest)
Prince Charles is reportedly "sickened" by the loud declaration of ex-royal familiar Tara Palmer-Tomkinson that she did not have sex with Prince William. Nobody is known to have accused her of such, but she cited gossip as leaving her with "a bad case of rumortism."
—“Bloody Boisterous,” San Jose Mercury News, October 13, 1999