/jif' kl/, /jaf' kl/, /j*-fi' kl/ (obsolete) To cancel or annul something. "Why don' t you jfcl that out?" The fastest do-nothing instruction on older models of the href="module.php?name=Lexikon&file=search&eid=1&query=PDP-10">PDP-10happened to be JFCL, which stands for "Jump if Flag set and then CLear the flag" this does something useful, but is a very fast no-operation if no flag is specified. Geoff Goodfellow, one of the jargon-1 co-authors, had JFCL on the licence plate of his BMW for years. Usage: rare except among old-time PDP-10 hackers. [href="module.php?name=Lexikon&file=search&eid=1&query=Jargon File">Jargon File] (1994-11-22)