threatening (adj.)

• abusive
• alarming
• apocalyptic
• approaching
• bad
• baleful
• baneful
• black
• blustering
• boding
• bullying
• close
• coming
• comminatory
• critical
• dangerous
• dark
• denunciatory
• dire
• dreary
• evil
• explosive
• fateful
• foreboding
• forthcoming
• future
• gathering
• gloomy
• ill
• ill-fated
• ill-omened
• ill-starred
• immediate
• imminent
• impendent
• impending
• inauspicious
• instant
• intimidating
• looming
• lowering
• menacing
• minacious
• minatory
• near
• ominous
• parlous
• perilous
• portentous
• serious
• sinister
• somber
• ugly
• unfavorable
• unfortunate
• unlucky
• unpromising
• unpropitious
• untoward
• upcoming
• waiting