a signal (often a sound) that shows that a place or situation is no longer dangerous 解除警报；警报解除信号 The children hid in the basement until the all-clear sounded. 孩子们躲在地下室，直到所有的声音都响了。
if a doctor gives somebody the all-clear, they tell the person that he/she does not have any health problems 没有疾病；完全健康 - (figurative)
The building was given the all-clear following tests. 对该建筑物进行了以下所有清晰测试。
- (figurative)
permission to do something 准许；许可