/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 PDP-10 happened 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.[Jargon File](1994-11-22)