Where does “pergravis” come from?

pergravis (Latin) comes from Latin gravis, from Proto-Indo-European gʷréh₂us, from Proto-Indo-European -us — Forms adjectives from Caland system roots.

pergravis (Latin): very heavy; very troublesome; very grave

Definitions

very heavy; very troublesome; very grave

Ancestry of “pergravis”, step by step

Step	Language	Word	Meaning
1	Latin	gravis	heavy; troublesome, hard; grave, serious
2	Proto-Indo-European	gʷréh₂us	heavy
3	Proto-Indo-European	-us	Forms adjectives from Caland system roots

Every word from Proto-Indo-European -us →Every word from Proto-Indo-European gʷréh₂us →Every word from Latin gravis →