mail bomb
noun
1.
letter bomb
.
2.
Also called
e-mail bomb
. a very large number of e-mails sent to a single e-mail address or computer network, usually causing a server or system crash.
verb (used with object), verb (used without object)
3.
Also,
mail-bomb
. to send a mail bomb to (an e-mail address or computer network).
Origin
1970-75