Where does “lerdão” come from?

lerdão (Portuguese) comes from Portuguese lerdo, from Spanish lerdo, from Late Latin lurdus, from Latin luridus, from Latin luror, from Proto-Italic *loiros.

Ancestry of “lerdão”, step by step

Step	Language	Word	Meaning
1	Portuguese	lerdo	slow; stupid
2	Spanish	lerdo	slow, sluggish, of animals; dim-witted, oafish,...
3	Late Latin	lurdus	slow; stupid; slow, heavy; clumsy, stupid
4	Latin	luridus	pale yellow, wan, sallow, lurid; ghastly,...
5	Latin	luror	paleness, pallor, lividness
6	Proto-Italic	*loiros	—

Every word from Proto-Italic *loiros →