(of a piece of equipment) no longer functioning, especially because of a fault.

the phone had gone dead

(of a place or time) characterized by a lack of activity or excitement.

Brussels isn't dead after dark, if you know where to look

(of sound) without resonance; dull.

the note sounds dead compared to all others on the keyboard

absolutely; completely.

you're dead right

complete; absolute.

we sat in dead silence