Chikan (痴漢, チカン, or ちかん) is a Japanese term referring to an obscene act conducted against the victim's will, or a person who commits such an act. The term is frequently used to describe men who take advantage of the crowded conditions on the public transit systems to touch people sexually. While the term is not defined in the Japanese legal system, vernacular usage of the word describes acts that violate several laws. The neologism referring to the corresponding female chikan is chijo. In clinical psychology, this desire is called frotteurism. Although women on crowded trains in Japan are the most frequent targets of chikan, sexual predators in Japan can take advantage of people of either sex in other situations as well. One such situation (warned against in the sign depicted to the right)