Mokusatsu (黙殺?) is a Japanese noun literally meaning "kill" with "silence", and is used with a verb marker idiomatically to mean "ignore", "take no notice of" or "treat with silent contempt". It is composed of two kanji characters: 黙 (moku "silence") and 殺 (satsu "killing").
Despite being a word of Japanese origin, Mokusatsu is also understood in the Western world when it is used in conjunction with the Potsdam Declaration.
The government of Japan used the term as a response to Allied demands in the Potsdam Declaration for unconditional surrender in World War II, which led to President Harry S. Truman's decision to carry out the atomic bombings of Hiroshima and Nagasaki.
Mokusatsu was employed in the morning edition of the Asahi Shinbun during World War II on July 28, 1945, to designate the attitude assumed by the government to the Potsdam Declaration. This newspaper and others had been quick to announce that the Declaration had been rejected by Japan, since the ultimatum (in addition to being transmitted to the Japanese government diplomatically via Swiss intermediaries) was transmitted via radio and airdropped leaflets to the Japanese public. It is questionable whether the Japanese press were acting on reliable government sources when they first announced the Declaration's rejection. Later that day in a press conference, the word was again used by the Premier Kantarō Suzuki to dismiss the Potsdam Declarations as a mere rehash of earlier rejected Allied proposals, and therefore, being of no value, would be killed off by silent contempt (mokusatsu). According to John Toland, Suzuki's choice of the term was dictated more by the need to appease the military, which was hostile to the idea of "unconditional surrender", than to signal anything to the Allies. Suzuki's actual words were: