Where does “tineosus” come from?

tineosus (Latin) comes from Latin Tinea, from Proto-Indo-European teh₂w- — to melt.

Ancestry of “tineosus”, step by step

Step	Language	Word	Meaning
1	Latin	Tinea	—
2	Proto-Indo-European	teh₂w-	to melt

tineosus — Etymology, Origin & Word History | Etymology Explorer