Porteño Spanish is the dialect of caste-sha-no (castellano) spoken in Buenos Aires, Argentina and the surrounding areas. It is categorized by an Italian-like pronunciation and colorful Lunfardo slang.Browse Slang Dictionary
a gathering of fools
This comes from the legendary Gauchito Gil, a folkloric saint and Robin Hood-esque character popular especially among the northern provinces of Corrientes, Formosa, Chaco and Santa Fe.
The word "gil" has come to mean "silly" or "foolish". Often this attributed to Gauchito Gil, but some etymological account claim it comes from the Caló or Iberian Gypsy word "Jili" which means "innocent". (This is also the basis for the Spanish slang "gilipollas".) It is likely that "gil" meaning "fool" comes from both.
Adding the suffix "~ada" makes it in the past participle of its verb form and means "a gather of fools". It's unclear if this comes from the yearly festivals in Gauchito Gil's honor, or his folk patron saint day.