Jap is an English abbreviation of the word "Japanese". Today, it is generally regarded as an ethnic slur. In the United States, some Japanese Americans have come to find the term very offensive, even when used as an abbreviation. Prior to the Attack on Pearl Harbor, Jap was not considered primarily offensive. However, following the bombing of Pearl Harbor and the Japanese declaration of war on the US, the term began to be used derogatorily, as anti-Japanese sentiment increased. During the war, signs using the epithet, with messages such as "No Japs Allowed", were hung in some businesses, with service denied to customers of Japanese descent.