'baleful' originates from Old English, specifically the word 'bāl', where 'bāl' meant 'evil, disaster, woe' and the suffix '-ful' meant 'full of.'

'baleful' developed from Old English 'bāl' (noun) which became Middle English 'bale' (meaning harm or calamity), and the adjective 'baleful' was formed to mean 'full of bale/woe,' evolving into modern English 'baleful.'

Initially, it meant 'full of woe or evil' (literally 'full of bale'); over time the sense shifted and narrowed to 'threatening harm' or 'ominous' in modern usage.