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
good looking; fashionable
This comes from the word "facha", which means "look" or "appearance". Literally, the phrase "Valentin es un fachero" translates as "Valentine is a looker", but implies also he is trendy and well put together.
Interestingly, "facha" is also the root word for "fascist", but calling someone a "fachero" has no political connotations.