"sinister cloud" is a correct and usable phrase in written English.
You may use it to refer to an ominous or foreboding feeling or atmosphere. For example: The sinister cloud of uncertainty loomed over the town after the factory announced it would be closing.
Rob's abuse has bloomed from the occasional controlling demand into a mushroom cloud of sinister, coercive behaviour.
As a city London assumes a sinister, mediocre drabness whose incessant cloud cover and soft light provide a lenient blanket for the parasitic criminal network of expatriate Russian wiseguys who find it a congenial base.
The child of a Presbyterian missionary to China, she grew up amid bandits, beggars, lepers, typhoons, floods, rebellions, famine, sinister mobs, marauding soldiers, opium clouds.
You warmed up our heart, you broke the clouds of a sinister mediocrity, and you showed us the very best of man's nature.
Instead of Orwell's intellectuals and bureaucrats clouding their true, sinister meaning "like a cuttlefish squirting out ink," we have television personalities disguising the emptiness of their thoughts with a set of pre-baked homespun idioms, or else with a technical campaign vocabulary that gives a false impression of privileged knowledge.
Through a mix of cute animation, live action, shadow and actual puppetry - but no words - PTC tell the story of an old man who's losing his memory; it puffs away in little cotton wool clouds, which a seemingly sinister cowboy catches in a net.
The View of Toledo (c. 1595) renders a city stormy, sinister, and impassioned with the same dark, foreboding clouds that appear in the background of his earlier Crucifixion with Donors.
They also sought reassurance after the sinister shadow that saw off Ramón Calderón cast a cloud over Catalunya.
Another senior KLA veteran, Ramush Haradinaj, was shot and wounded on July 7th a sinister sign of strife among Kosovars.With all these clouds on the horizon, what hope do Balkan countries have, in the language of Brussels, of "joining Europe's mainstream"?
When I last visited the park, dark, foreboding clouds hung above it, adding an even more sinister element to its decay.
