Where does “activus” come from?

activus (Latin) comes from Ancient Greek ἐνεργητικός, from Ancient Greek ἐνεργέω, from Ancient Greek ἐνεργός, from Ancient Greek ἐν-, from Ancient Greek ἐν, from Ancient Greek δέρμα, from Ancient Greek γλυφή, from Ancient Greek -ῐ́ᾱ — Creates collective nouns, which refer to groups...

Ancestry of “activus”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	ἐνεργητικός	Able to act on; acting on; Active; In the active...
2	Ancient Greek	ἐνεργέω	to be in action or activity, to operate; to...
3	Ancient Greek	ἐνεργός	at work, active
4	Ancient Greek	ἐν-	in, within; on
5	Ancient Greek	ἐν	in, on, at; among; in, at, or during the time of
6	Ancient Greek	δέρμα	skin, hide
7	Ancient Greek	γλυφή	carving, carved work; hole cut
8	Ancient Greek	-ῐ́ᾱ	{{l\|en\|-ia}}; "suffix forming abstract feminine...
9	Proto-Indo-European	-íh₂	—
10	Proto-Indo-European	-h₂	Creates collective nouns, which refer to groups...

Every word from Proto-Indo-European -h₂ →

activus — Etymology, Origin & Word History | Etymology Explorer