Grosero vs. maleducado vs. rudo
The Spanish words 'grosero', 'maleducado' and 'rudo' all translate to 'rude' or 'bad-mannered' in English, but they are used in slightly different contexts and have different connotations.
Grosero
'Grosero' refers to someone being rude or offensive in a vulgar or indecent manner. It is often used to describe someone's crude language, gestures or behavior.
No toleraré tus comentarios groseros.
(I will not tolerate your rude comments.)
Su comportamiento grosero fue totalmente inaceptable en la cena.
(His crude behavior was totally unacceptable at dinner.)
Maleducado
'Maleducado' suggests that someone is inadequately or improperly educated. This implies not merely rudeness, but ignorance of basic social etiquette or manners.
El hombre maleducado interrumpió constantemente la conversación.
(The uneducated man constantly interrupted the conversation.)
Ella es muy maleducada, nunca dice "por favor" o "gracias".
(She's very rude, she never says 'please' or 'thank you'.)
Rudo
'Rudo' is used to describe someone who is harsh, unsophisticated, or lacks refinement in their actions or language.
El vendedor fue rudo con los clientes.
(The salesman was rude to the customers.)
Es rudo levantar la voz cuando estás enojado.
(It's rude to raise your voice when you're angry.)
Summary
'Grosero', 'maleducado', and 'rudo' all refer to different aspects of rudeness. While 'grosero' implies vulgarity and offensiveness, 'maleducado' refers more to a lack of good manners due to poor upbringing, and 'rudo' implies harshness or a lack of refinement.