From Longman Dictionary of Contemporary Englishhate mailˈhate mail noun [uncountable]letters that express a lot of hatred towards the person to whom they are sentShe complained to the police after receiving hate mail.Examples from the Corpushate mail• From the early days Kylie was plagued by obscenephone calls and hate mail.• The ones still alive send me hate mail in Liverpool.• Anti-Semitic hate mail sent to an elementary school student in Benicia by classmates.• I was wondering, would you know if any other subscriber to the hunt had receivedsimilarhate mail?