mail bomb
noun [ C ]
IT ukus(also email bomb)an occasion when many email messages are sent to a single address at the same time, for example as a way of complaining or showing anger about something, or in order to annoy someone:
Mail bombs choked the mail server and made it impossible for us to get our real messages.
mail-bomb
verb [ T ]
Spammers mail-bombed the trade commission as a way to protest the investigation.