Cool
Very common in Mexico. Use it as a reaction, like 'Cool!' or 'How cool!'. Literally means 'how father'.
A universal word for 'great' or 'brilliant' that is understood everywhere. It's less slangy than other options.
Very popular in South American countries like Colombia, Chile, and Peru.
Another very popular, casual slang term used in Mexico.
Your new car is very cool.
Let's go to the beach? Cool!
The idea is great/cool.
That place is very cool.
Your shoes are cool.
'Chévere' and 'genial' are the most widely understood. 'Chévere' is very common in the Caribbean and northern South America (Colombia, Venezuela, Peru).
The most common expressions are 'qué padre' and 'chido'. 'Chévere' is understood but sounds foreign.
The primary word is 'guay'. They also use 'chulo/a' for objects/people or the verb 'molar' (e.g., 'esto mola' means 'this is cool').
'Chévere' and 'bacano' are both extremely common and used interchangeably.
Argentinians say 'copado' or 'qué bueno'. They also use 'bárbaro' to mean fantastic or great.
The main slang word for 'cool' is 'bacán'.
Using 'frío' to mean cool. — 'Frío' only refers to temperature (e.g., 'agua fría' for 'cold water'). To describe something as cool/great, you must use a word like 'chévere' or 'genial'.
Using a regional word in the wrong country. — Saying 'qué padre' in Spain isn't grammatically wrong, but it will sound strange. It's best to listen and adapt to the local slang of the country you're in.
Forgetting gender agreement with adjectives. — Some words for 'cool' are adjectives and must match the noun. For example: 'La fiesta está bacana' (The party is cool), not '...bacano'. Words like 'chévere' and 'genial' don't change for gender, which makes them easier.