portentous (adj) - ominous, or threatening; self-consciously serious or solemn; momentous [pawr-ten-tuhs]
BREAKDOWN: POR- (forth) + TENS- (stretch) + -OUS (full of)
portent is a sign or omen of a positive or negative future event, often of a significant or divine nature
portend means to signal a significant future event, either positive or negative; to foretell or foreshadow
See also: ostensible, pretentious, tendentious, tenuous
“He to whom the portentous conspiracy of night and solitude and silence in the heart of a great forest is not an unknown experience needs not to be told what another world it all is - how even the most commonplace and familiar objects take on another character.” —Ambrose Bierce
