Where does “mercabilis” come from?

mercabilis (Latin) comes from Latin mercārī, from Latin merx, from Proto-Italic *merks.

Ancestry of “mercabilis”, step by step

Step	Language	Word	Meaning
1	Latin	mercārī	—
2	Latin	merx	merchandise, commodity; goods, wares
3	Proto-Italic	*merks	—

mercabilis — Etymology, Origin & Word History | Etymology Explorer