(n.) That which portends, especially that which portends evil; a sign of coming calamity; an omen\; a sign.

adumbration advance notice augury auspice balefulness banefulness betokening betokenment bodefulness boding direness doomfulness fatality fatefulness foreboding foreshadow foreshadowing foreshowing foretoken foretokening forewarning indicant indication marvel meaning miracle omen ominousness phenomenon plenty of notice portentousness precautioning prefiguration preindication premonition premonitory shiver premonitory sign premonitory symptom prenotice prenotification presage presagefulness presentiment presignifying prewarning prodigy prognostic prognostication promise sensation shadow sign significance sinisterness soothsay stunner suggestiveness token tokening type