Where does “acerrimus” come from?

acerrimus (Latin) comes from Latin acer, from Proto-Italic akris, from Proto-Indo-European *h₂eḱrós, from Proto-Indo-European h₂eḱ- — sharp.

acerrimus (Latin): sharpest; bitterest

Definitions

Step	Language	Word	Meaning
1	Latin	acer	sharp, sour, bitter, pungent; keen, sharp, acute,...
2	Proto-Italic	akris	sharp; sour-tasting
3	Proto-Indo-European	*h₂eḱrós	—
4	Proto-Indo-European	h₂eḱ-	sharp

acerrimus — Etymology, Origin & Word History | Etymology Explorer