two thin wires crossing each other in a gun or other device, which you use to help you aim at something

A sniper had them in his crosshairs. 一个狙击手瞄准了他们。

The poster showed his face in the crosshairs of a rifle. 那张海报里，他的脸被放在步枪瞄准线上。

in someone's crosshairsidiom 成为……的靶子（因此会被抓住、逮捕或者阻止）