The word "lowkey" is an informal term often used to describe something that is not intended to attract a lot of attention or is done in a subtle, understated way. It can also refer to a feeling or sentiment that is somewhat reserved or discreet, and it may imply that something is intentionally kept off the radar or is not meant to be overly emphasized.
The term "lowkey" originated in African American Vernacular English (AAVE) in the early 2000s. It is believed to be a merging of “low” (meaning discreet) and “key,” which in this context means to keep something secret or private. Over time, it has entered mainstream slang usage.