What is "envelope stuffer"

alt. 1 One whose job is to manually insert sheets of printed paper into envelopes for mailing, especially as an example of a person whose work is menial and unfulfilling. 2 A machine that mechanically insert sheets of printed paper into envelopes. 3 An advertisement, flyer, or other unsolicited printed material contained in an envelope received by mail. n. 1 One whose job is to manually insert sheets of printed paper into envelopes for mailing, especially as an example of a person whose work is menial and unfulfilling. 2 A machine that mechanically insert sheets of printed paper into envelopes. 3 An advertisement, flyer, or other unsolicited printed material contained in an envelope received by mail.