low-key

Dark; characterized by dark tones and muted colors.

The classic example of low key photography is a black cat in a coal cellar. […] The most popular use of low-key photography is in making portraits of celebrities or theatrical personalities. These people demand either dignity or drama, and this type of lightning is appropriate for both.

Restrained, subtle, not trying to attract attention.

She deserves an Oscar for her low-key performance in that movie.

For a low-key, somewhat predictable meal, dinner at Basem's offers good value.

Used as a downtoner; kind of.

I'm low key salty about the way that nigga did you but it seems like he still cares about you.

Before I open the messages, I disable the activity notification so no one will know I'm low-key obsessed with a party I didn't get to attend.

Actually; seriously.

Lowkey if you talk about any woman like this you gotta die

In a low-key or surreptitious manner; secretively; understatedly; on the down-low.