'doomsaying' originates from Old English, specifically from 'dōm' (doom) meaning 'judgment, law, fate' and 'secgan' (say) meaning 'to say'; the modern compound combines these roots with the -ing suffix to denote the act of saying doom.

'doom' developed from Old English 'dōm' into Middle English 'dom' meaning 'judgment' or 'fate'; compounds and verbs formed with 'say'/'sayen' later produced words like 'doomsay' and the verbal/noun form 'doomsaying' in later English.

Initially, 'doom' referred primarily to 'judgment' or 'legal decision' and 'doomsaying' would have implied pronouncing a judgment; over time the sense shifted toward predicting ruin or catastrophe, giving the modern meaning 'proclaiming disaster or hopeless outcomes.'