old wives' tale noun
plural ∼ tales [count] disapproving : a common belief about something that is not based on facts and that is usually false
▪ Frogs won't give you warts. That's just an old wives' tale. ▪ the old wives' tale about the full moon causing people to act crazy — compare superstition
▪ Frogs won't give you warts. That's just an old wives' tale. ▪ the old wives' tale about the full moon causing people to act crazy — compare superstition
