Gíria vs. calão
While both terms relate to non-standard language, usage varies significantly by region. Gíria is the standard term for casual slang in Brazil and Portugal. Calão, however, usually implies vulgarity or swear words in Portugal, whereas in Brazil, it is a formal term almost exclusively used to describe profanity.
Gíria
B1In both Brazil and Portugal, gíria refers to informal slang, social jargon, or colloquiums used by specific groups (like teenagers, surfers, or professionals). It is generally acceptable in casual conversation and is not considered offensive.
Os adolescentes usam muita gíria que os pais não entendem.
(Teenagers use a lot of slang that parents don't understand.)
Cada profissão tem a sua própria gíria técnica.
(Every profession has its own technical jargon.)
Calão
C1In Portugal, calão is commonly used to describe crude, vulgar language or swear words. In Brazil, calão is a formal, almost technical word that is rarely used alone; it appears mostly in the phrase baixo calão to formally describe profanity or dirty words.
Ele foi expulso da sala por usar calão com o professor.
(He was kicked out of the room for using bad language with the teacher.)
O uso de palavras de baixo calão é proibido na televisão.
(The use of profane words is prohibited on television.)
Não gosto quando usam tanto calão em conversas sérias.
(I don't like it when they use so much vulgar slang in serious conversations.)
O juiz advertiu o advogado sobre a linguagem de baixo calão.
(The judge warned the lawyer about the profane language.)
Evite o calão quando estiver numa entrevista de emprego.
(Avoid swear words when you are in a job interview.)
Summary
Use gíria for innocent, everyday slang in both countries. Use calão in Portugal if referring to swear words or vulgar dialect. In Brazil, avoid calão in daily speech; use it only if you need to formally threaten someone for using palavras de baixo calão (profanity).