lowkey

"Lowkey" describes something done in a quiet, subtle, or modest way. It often refers to keeping information private, avoiding unnecessary attention, or expressing a feeling that is present but not being shouted from the rooftops. Imagine dimming the lights in a room; you aren't turning them off, just making them less intense. In modern usage, it often functions as an adverb meaning "secretly" or "mildly." If you "lowkey" like a certain song, you enjoy it but might not admit it to everyone because it’s a bit of a guilty pleasure. It is strictly informal and very common in text messaging and social media contexts.
In conversation
Discussing a crush
Are you going to ask Sarah out?
Are you going to ask Sarah out?
I lowkey have a crush on her, but I'm too nervous.
I secretly have a crush on her, but I'm too nervous.
Used here to express a feeling that is present but kept quiet.
Planning a weekend
Are you doing anything big for your birthday?
Are you doing anything big for your birthday?
Nah, keeping it lowkey this year. Just dinner.
Nah, keeping it simple this year. Just dinner.
Used here to describe a plan that is modest and lacks fanfare.
Examples
I lowkey think this movie is better than the first one.
I secretly think this movie is better than the first one.
Let’s keep the celebration lowkey until we get the official news.
Let’s keep the celebration quiet until we get the official news.
He is lowkey the most talented person in the room, despite his humble demeanor.
He is quietly the most talented person in the room, despite his humble demeanor.