Expressing bad consequences: dreadful; dismal.
Warning of bad consequences: ill-boding; portentous.
Bad in quality, awful, terrible.
Requiring action to prevent bad consequences: urgent, pressing.
Ghastly or sinister.
Rigid and unrelenting.
Disgusting; gross.
Dismal and gloomy, cold and forbidding.
To make grim; to give a stern or forbidding aspect to.