Foreboding is a powerful word that evokes a sense of fear or apprehension for something that may happen in the future. However, it's always good to have alternatives to use in various writing contexts. Potential synonyms for foreboding may include premonition, ominous, prophecy, boding, portent, apprehension, bad vibes, unease, and apprehensiveness. Other synonyms could include prediction, warning, harbinger, ill-boding, an omen, or a sign, among others. Regardless of which synonym is used, they all have in common the sense of some negative event or situation that may unfold in the future. Ultimately, writers should choose the best synonym that accurately conveys the desired tone and context.