BTFU = Back The F*ck Up... Defensive reaction; Surprised by sudden confrontation; Akin to: "Step Off"; "Get Outta My Face"; "Back Off"
Or as in surprised reaction to seemingly outrageous news within social groups;
Akin to: "No Way"; "Get Out"; "Shut The Front Door"
AnonOne's Urban Survival Kit for dummies Vol. II. 2018 appendix