An intensity modifier or hedge word: "lowkey" = somewhat, quietly, I'm willing to admit but not yell it; "highkey" = very, openly, loud and proud. "I lowkey want to cry" = "I kinda want to cry, but I'm not going to make it a scene." "I highkey love this sermon" = "I unreservedly love this sermon."
"Lowkey" and "highkey" are pure intensifiers, like "kind of," "sort of," "very," "extremely." No theological implication in either direction. Christian speech should still be precise and honest — Christians should not hedge genuine convictions with "lowkey" to avoid social cost ("I lowkey think abortion is murder" when they should just say so) — but the word itself is morally neutral.
Gen-Z has more granular adverbs for feelings than any previous generation; "lowkey / highkey" is a handy pair with no hidden agenda.
Vocabulary inflation is everywhere online, and "lowkey / highkey" are part of Gen-Z's hyper-specific adverb toolkit. The watch-out is the hedge function: using "lowkey" to soften a conviction until it has no bite. A Christian who "lowkey" believes the resurrection is not a Christian who believes the resurrection; the word has become a hedge against social cost. Use the modifier in neutral contexts; drop it when clarity is required. Your yes is yes; your no is no. Lowkey is fine when you truly mean "somewhat"; it is cowardice when you use it to dilute what you actually believe.
Matthew 5:37 — "Let what you say be simply 'Yes' or 'No'; anything more than this comes from evil."
Revelation 3:16 — "So, because you are lukewarm, and neither hot nor cold, I will spit you out of my mouth."
Colossians 4:6 — "Let your speech always be gracious, seasoned with salt, so that you may know how you ought to answer each person."
"Lowkey" is fine for moods. It is a trap for convictions. Saying you "lowkey" believe in Christ is not believing in Christ; saying you "lowkey" disagree with sin is not disagreeing. Convictions are binary; feelings have dials.
“Lowkey this chapel speaker is kinda fire.”
“Let your yes be yes and your no be no.”