blacken
verb
Blacken means to make something dark or black in color. It can be used to describe coloring a picture with a crayon or paint, or to describe a person's skin getting darker from being in the sun.
Example
- I blackened the bottom of the pot while cooking the stew.
- The soot from the fire had blackened the walls of the room.
- She blackened her eyelids with a smoky eye look.