Jalisco isn't a slang term. It's the name of a state in Mexico. However, it's associated with a saying 'Jalisco nunca pierde y si pierde arrebata' which translates to 'Jalisco never loses and if it loses, it snatches'. It's used to describe someone competitive and unwilling to accept defeat.
Examples
- Spanish: Juan es muy competitivo, como bien dice el dicho, 'Jalisco nunca pierde y si pierde arrebata'.
- English: Juan is very competitive, as the saying goes, 'Jalisco never loses and if it loses, it snatches'.