Melo/a

A way to say "cool", but in a very casual way. Commonly used by low class "ñeros".

It can variate when it's used as a superlative (it's an adjective) and it depends of the gender of the noun.
Used in Colombia.
If yor hear someone saying it, run or you'll lose yor phone and money.

"Estuvo melo/a" (It was cool)
"Es melísimo/a". (It's cool)