From Longman Dictionary of Contemporary Englishhellishhell‧ish /ˈhelɪʃ/ adjective informal BADextremely bad or difficult I’ve had a hellish day at work. —hellishly adverb a hellishly difficult exam
Examples from the Corpus
hellish• Chilly mornings stretched into hellish afternoons as temperatures hovered around 100 degrees.• Rehearsals were hell - although not quite as hellish as the first performances in Cambridge.• The New York Rangers had a hellish December, playing 17 games in 31 days, and now are coasting in comparison.• Installing a hard drive is not the hellish endeavor it once was, grizzled hardware veterans tell me.• five hellish months in the prison• If that unbidden calamity befell them, they would glumly accept what looked to be a hellish process.• They are heading directly back towards the hellish towers of Castle Drachenfels.• The office block was in the middle of a hellish whirlwind. 