you shouldn't speak ill of the dead

you shouldn't speak ill of the dead

It is immoral or objectionable to say malicious or defamatory things about someone who has passed away. A: "Ah, Tom was just a selfish old bigot." B: "Mary! You shouldn't speak ill of the dead!" You say we shouldn't speak ill of the dead, but we shouldn't forget the misdeeds of those who were once in power, either, lest history repeats itself.
See also: dead, ill, of, speak