(as) black as (one's) hat old-fashioned simile
Completely black; totally dark
This place looks so creepy, it's as black as my hat!
I can't see anything in this tunnel, it's as black as my hat.
Completely dark, without any light or color
Completely black, without any light or other color
Completely dark
To bear too many problems or responsibilities
I am carrying the weight of the world on my shoulders as I am the last participant who will to win or to lose our team.