Where does “strenuosus” come from?

strenuosus (Latin) comes from Latin -ōsus, from Old Latin -ōssus.

Ancestry of “strenuosus”, step by step

Step	Language	Word	Meaning
1	Latin	-ōsus	ose, -ous, -ful (full of or overly prone to)
2	Old Latin	-ōssus	—