Where does “horrescens” come from?

horrescens (Latin) comes from Latin horrēscō, from Latin -sco, from Proto-Italic -skō, from Proto-Indo-European -sḱéti — Forms durative or iterative imperfective verbs...

Definitions

Ancestry of “horrescens”, step by step

Step	Language	Word	Meaning
1	Latin	horrēscō	to begin to bristle up; one's hair rises on end
2	Latin	-sco	Forms inchoative verbs from existing verbs,...
3	Proto-Italic	-skō	—
4	Proto-Indo-European	-sḱéti	Forms durative or iterative imperfective verbs...

Every word from Proto-Indo-European -sḱéti →Every word from Latin -sco →Every word from Latin horrēscō →