Interfere  v. (-ring) 1 (usu. Foll. By with) a (of a person) meddle; obstruct a process etc. B (of a thing) be a hindrance. 2 (usu. Foll. By in) intervene, esp. Without invitation or necessity. 3 (foll. By with) euphem. Molest or assault sexually. 4 (of light or other waves) combine so as to cause interference. [latin ferio strike]