Buy an Antiwar Anti-War calligraphy wall scroll here!
反戰 means antiwar, as in what a pacifist believes in.
China does plenty of saber-rattling but thankfully doesn't go to war very often, and Japan has embraced a pacifist ideology. Therefore, it's rare to need this word. However, this is the kind of word that war protesters would write on their signs.
There is a modern Japanese version of the second character which has become the standard in Japan after WWII. If you want your calligraphy written in the modern Japanese form, please click on the Kanji shown to the right instead of the button above. Note: Most Japanese and all Chinese people will recognize the form shown in the upper left.