Slang term for spam e-mail address, a person’s secondary e-mail address, which is used for registering to receive newsletters, discussion forums and for other Web sites requiring sign-ups where you may receive frequent e-mails. The spamdress is used in place of a primary e-mail address to assist in keeping spam out of the primary account. Also called spamaddress.
Also see Getting Rid of Spam in the Did You Know section of Webopedia.