Nyx Off
An angry verbal response when one feels disrespected and carries much angst towards the instigator. Not to be confused with "fuck off," "nyx off" is a much stronger reply with perennial hatred and anxiety.
Person A: I have an annoucement to make. My exepectations are that you all will abide by my rules.
Person B: Nyx off.
Person B: Nyx off.