proviso
noun [ C ] uk/prəˈvaɪ.zəʊ/ us/prəˈvaɪ.zoʊ/ provisos
限制性条款;附文;但书
a statement in an agreement, saying that a particular thing must happen before another can
[ + that ] He was released from prison with/on the proviso that he doesn't leave the country. 他获释出狱了，但前提条件是不能出国。