
1) Abusive correspondence 2) Angry letters 3) Form of intimidation 4) It may include a death threat 5) Letters that are hard to read 6) Nasty letters 7) Nastygrams 8) Poison-pen letters 9) Some anonymous letters 10) Some written rants 11) Unwanted messages 12) Venomous letters
Found on
https://www.crosswordclues.com/clue/hate-mail

Hate mail (as electronic, posted, or otherwise) is a form of harassment, usually consisting of invective and potentially intimidating or threatening comments towards the recipient. Hate mail often contains exceptionally abusive, foul or otherwise hurtful language. The recipient may receive disparaging remarks concerning their ethnicity, sexuality,...
Found on
http://en.wikipedia.org/wiki/Hate_mail
noun mail that expresses the writer`s dislike or hatred (usually in offensive language)
Found on
https://www.encyclo.co.uk/local/20974
No exact match found.