Italian word terribile comes from Proto-Indo-European *strēy-, and later Latin terribilis (Frightful, dreadful, terrible.)

Detailed word origin of terribile

Dictionary entry	Language	Definition
*strēy-	Proto-Indo-European (ine-pro)
*tres-	Proto-Indo-European (ine-pro)
terreo	Latin (lat)	I deter by terror, scare (away). I frighten, terrify, alarm.
terribilis	Latin (lat)	Frightful, dreadful, terrible.
terribile	Italian (ita)	Horrible, awful, dreadful. Terrible, terrifying, fearful. Terrific.