'bad' originates from Middle English, probably from Old English 'bæddel' (recorded forms vary), where the original term referred to an 'effeminate person' or 'hermaphrodite' (exact origin uncertain).

'bad' changed from Old English 'bæddel' to Middle English forms such as 'bad'/'badde' and eventually became the modern English word 'bad'.

Initially associated with a personal/pejorative sense ('effeminate person' or similar), the word's meaning shifted over time to express moral poor quality, evil, or poor condition — the current core senses of 'bad'.