If you describe a place or a period of time as dead, you do not like it because there is very little activity taking place in it.
无生气的
Dead means "precisely" or "exactly."
精确地 • Mars was visible, dead in the centre of the telescope. 火星清晰可辨,正好就在望远镜的中心。
The dead are people who are dead.
死者 • Two American soldiers were among the dead. 死者中有两名美军士兵。