(a.) Being or exhibiting an omen; significant; portentous; foreboding or foreshowing evil; inauspicious; as, an ominous dread\.

abusive admonitory apocalyptic augural bad badly off baleful baneful black bludgeoning blustering bodeful boding browbeating bulldozing bullying cautionary comminatory corroding corrosive corrupting corruptive counterproductive damaging dark deadly deleterious denunciatory depressed detrimental dire direful disadvantageous disserviceable distressing donsie doomful dreary evil evil-starred fatal fateful fear-inspiring forbidding foreboding foreshadowing foretelling foretokening fortuneless funest gloomy grim hapless harmful hectoring hostile hurtful ill ill off ill-boding ill-fated ill-omened ill-starred imminent in adverse circumstances inauspicious indicative inhospitable injurious intimidating lethal lowering luckless malefic maleficent malevolent malign malignant mantic meaningful menacing minacious minatory mischievous noisome noxious of evil portent oracular out of luck pernicious planet-struck poisonous portending portentous predictive prejudicial premonitory prognostic prophetic sad scatheful short of luck sibyllic sinister somber star-crossed terroristic terrorizing threatening threatful toxic unblessed underprivileged unfavorable unfortunate unfriendly unhappy unlucky unpromising unpropitious unprosperous unprovidential untoward vaticinal venenate veneniferous venenous venomous vicious virulent warning