We' re living in a den of thieves

[Conoscenza SIlente]

Hi All
do you know what does the idiom "We' re living in a den of thieves" mean and in which context it is used?
Can it be used in formal occasions or it is best to use it with strict friends?
Thanks

[susiedqq]

den = dwelling place

Thieves would hide. They would hide in a dirty place. They usually are not good people.

So "living in a den of theives" would be staying or hanging out with not very good people in not very good circumstances.

(Is this a song lyric or book title?)

[manustone]

This sentence is taken from the song "US" by Regina Spektor