dead is a common English word with multiple meanings:
1. No longer alive (e.g. "The flowers are dead")
2. Completely, absolutely (e.g. "dead serious")
3. Not functioning (e.g. "dead battery")
4. Boring or dull (e.g. "dead party")
5. In sports - out of play (e.g. "dead ball")
6. Slang for very tired (e.g. "I'm dead after work")
7. In electronics - not carrying current (e.g. "dead wire")