It’s that time of year again, when Japanese people get out their lists of friends and business acquaintances in order to send out 年賀状 (nengajō), postcards that deliver seasonal greetings and well wishes for the new year. But some fear this tradition may soon disappear altogether.
According to recent reports, more and more people have been purchasing stamps and stickers that read 年賀状じまい (nengajō-jimai), which essentially announce the sender is opting out of the 年賀状 custom. You’ll find them stuck to the final 年賀状.
The suffix ~じまい (~jimai) comes from the verb 仕舞う (shimau), which means to put something away or to terminate it. The suffix is also seen in the words 店じまい (mise-jimai, going out of business) and 墓じまい (haka-jimai, dismantling a family tomb/grave).

AloJapan.com