The quality or state of being ominous or suggesting that something bad will happen; a sense of dread or premonition.
From 'forebode' (Old English 'forebodian': 'fore-' meaning before + 'bodian' meaning to announce) plus the suffix '-ingness' forming abstract nouns. The meaning evolved from literally 'announcing beforehand' to 'suggesting future misfortune' during the Middle English period.
Our ancestors believed that certain signs—a crow's call, unusual animal behavior, dreams—could literally announce disaster before it arrived. That's why we still use 'foreboding' for that eerie feeling that something bad is coming, even when we can't explain why.
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