low-key

From low +‎ key.

low-key (comparative more low-key, superlative most low-key)

1. (art, photography) Dark; characterised by dark tones and muted colours. [from 19th c.]
2. Restrained, subtle, not trying to attract attention. [from 20th c.]

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

   • 2019 November 14, Phil McNulty, “England 0-0 Brazil”, in BBC News‎:

     From the Samba band and colourfully-clad dancers that made a lap of Wembley before kick-off - even prompting some neat moves from one or two Brazilian journalists - to the roars of delight every time Neymar got on the ball, it was still a night that contained entertainment despite the increasingly low-key fare on the pitch.

While both low-key and high-key are commonly used in photography, high-key is not used in everyday usage. The term mid-key also exists in photography, but is much rarer.

• (photography): high-key

• (photography): mid-key

low-key (comparative more low-key, superlative most low-key)

1. (Canada, US, colloquial) A little; somewhat.
   • 2015, Lady Onyxx, Started From The Top Now I'm Here 3, page 81:

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

   • 2018, Rachel Vincent, Strange New World:

     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.

2. (slang) In a low-key or surreptitious manner; secretively; on the down-low

• furtively