Terrible is an English mis-translation...there are a lot of them. Grozny means feared. That is why the fortress in the south was named Grozny (then it became a city) as it was feared by the Chechen slave raiders.
Puttin' on my pedantic translator hat - Terrible is an acceptable translation. Groznyj actually means threatening or menacing. Strict translation would be Ivan the Fearsome. ;-)
So not infamous Russia Tsar but more like Tsar way back in da day before Ivan the terrible or after him I see
Yeah I like to know where they get the name Grozy