宣战xuān∥zhàn 1.一国或集团宣布同另一国或集团开始处于战争状态。{declare war; one country or one bloc of countries declare war on another country or bloc of countries} 2.泛指展开激烈斗争{(in a broad sense) launch a campaign against}: 他们向荒漠～,引水灌溉,植树造林。{They declared war on the wasteland by diverting water for irrigation and planting trees.}