Example : Grim determination.
Grim necessity.
Russia's final hour, it seemed, approached with inexorable certainty.
Relentless persecution.
The stern demands of parenthood.

Synonyms : inexorable, relentless, stern, unappeasable, unforgiving, unrelenting

Example : Ghastly wounds.
The grim aftermath of the bombing.
The grim task of burying the victims.
A grisly murder.
Gruesome evidence of human sacrifice.
Macabre tales of war and plague in the Middle ages.
Macabre tortures conceived by madmen.

Synonyms : ghastly, grisly, gruesome, macabre, sick

Example : Black humor.
A grim joke.
Grim laughter.
Fun ranging from slapstick clowning ... to savage mordant wit.

Synonyms : black, mordant

Example : A dour, self-sacrificing life.
A forbidding scowl.
A grim man loving duty more than humanity.
Undoubtedly the grimmest part of him was his iron claw.

Synonyms : dour, forbidding

Example : Gloomy at the thought of what he had to face.
Gloomy predictions.
A gloomy silence.
Took a grim view of the economy.
The darkening mood.
Lonely and blue in a strange city.
Depressed by the loss of his job.
A dispirited and resigned expression on her face.
Downcast after his defeat.
Feeling discouraged and downhearted.

Synonyms : blue, depressed, dispirited, down, down in the mouth, downcast, downhearted, gloomy, low, low-spirited

Example : A blue day.
The dark days of the war.
A week of rainy depressing weather.
A disconsolate winter landscape.
The first dismal dispiriting days of November.
A dark gloomy day.
Grim rainy weather.

Synonyms : blue, dark, dingy, disconsolate, dismal, drab, drear, dreary, gloomy, sorry