You use defensive to describe things that are intended to protect someone or something. 防御性的; 防卫用的
adjective [原级]防御的,戒备的;生气的,发怒的;(比赛中)防守的,防御的;百般辩解的
The Government hastily organized defensive measures, deploying searchlights and antiaircraft guns around the target cities. 政府匆忙组织了防御措施,在目标城市周围部署了探照灯和高射炮。
noun [抽象名词]防御态势,守势;辩护,辩解
The administration has been on the defensive about the war. 行政部门一直在为战争辩解。