What is "deepens"

Usage examples of "deepens".

As he looks at it, the darkness loses its two-dimensionality and deepens backward like a cave, or a black hole softly punched through the air.

Then their humming deepens, and the bottle begins to rise, wobbling from side to side like a tiny missile with a really shitty guidance system.

He catches me looking at him intently and his breathing deepens, as if shoving his handkerchief into his back pocket were an act of extreme exertion.

The molten light burning at the edges of the curtains and the window shades deepens the darkness of the long trailer's interior.

There is nothing I can do to make amends, which deepens my loneliness.