Where does “Rasta” come from?

Rasta (English) comes from English Rastafari, from Amharic ራስ ተፈሪ, from Amharic ራስ, from Proto-Semitic raʾš- — head.

Ancestry of “Rasta”, step by step

Step	Language	Word	Meaning
1	English	Rastafari	—
2	Amharic	ራስ ተፈሪ	—
3	Amharic	ራስ	head
4	Proto-Semitic	raʾš-	head