Añejo/a: A person who has not bathed. Here is a related expression: Más vale tierra en cuerpo que cuerpo en tierra. It is better to have dirt on your body than to be under the ground (dead).
Caco: A criminal. The expression El/la pinta is also used for criminal in Costa Rica slang
Cien metros or una teja: One block. Una teja is 100 colones and synonymous with one block. Cuadra is the correct word for a linear block. A manzana is a square block.
Estar jalando con alguien: To be dating or going out with a person.
Estar salado/a: To have bad luck. Más salado que moco de marinero or Más salada que pepita de ballena (vulgar) are a similar expressions. Tener mala suerte the correct way to express bad luck.
Gemelear: To copy or forge documents
Jacha: A derogatory word for face. Pichel and tarro are also used. Cara or rostro are the correct terms.
Jugarsela or se la juega: Is to know how to handle or manage something
Pasar por inocente como pan caliente: To be deceived or fall for something. Inocente or ingenuo mean naïve
Poner la chayotera: To sign something like a document or a check. Comes from the word chayote which is a succulent green pear-shaped tropical fruit that resembles cucumber in flavor.