Where does “mancargli” come from?

mancargli (Italian) comes from Italian mancare, from Vulgar Latin *mancāre, from Latin mancus, from Proto-Indo-European mank-.

Ancestry of “mancargli”, step by step

Step	Language	Word	Meaning
1	Italian	mancare	to lack; to be lacking; to be missing, absent
2	Vulgar Latin	*mancāre	—
3	Latin	mancus	maimed, crippled, handicapped, infirm; defective,...
4	Proto-Indo-European	mank-	—