Música: overkill

Hi Folks:

I was wondering the meaning of the word "overkill".
I've looked it up (dictionary), but I'd like to know a version.

It is from the song "Overkill"
Emerson Nogueira is a Brazilian singer who recorded that, by the way, he has an excellent accent and beautiful pronunciation.
Originally, the band is "Men at work".

'At least there's pretty lights
And though there's little variation
It nullifies the night
From overkill'

See you around!