Define it to Fight it Act of 2017 This bill directs the Department of State to withhold 10% of U.S. contributions to the regularly assessed biennial budget of the United Nations (U.N.) until the U.N. adopts a definition of international terrorism concurrent with U.S. laws. "International terrorism" means terrorism involving one or more citizens of a country, or the territory of one or more countries, if the government of any such country consents to, or with knowledge, allows, tolerates, or disregards the activities of that citizen or that use of the territory, including its use as a transit point.