Reprovar vs. chumbar
Both reprovar and chumbar express the idea of failing an exam or a school year. However, the main difference lies in their level of formality and the specific region where they are spoken.
Reprovar
A2This is the standard, formal term for failing. It is universally understood and used in both Brazil and Portugal. Reprovar is the neutral word you will see on official transcripts, school reports, and formal conversations.
O aluno reprovou de ano por excesso de faltas.
(The student failed the year due to excessive absences.)
Tenho medo de reprovar no exame de condução.
(I am afraid of failing the driving test.)
O professor decidiu reprovar quem não entregou o projeto.
(The teacher decided to fail anyone who did not submit the project.)
Ela estudou muito para não reprovar em matemática.
(She studied a lot so she wouldn't fail math.)
Chumbar
B2This is a colloquial, informal term specifically used in European Portuguese (Portugal). It is slang equivalent to to flunk. The literal root comes from chumbo (lead), implying that the student sank like a lead weight.
Ele não estudou nada e acabou por chumbar.
(He didn't study at all and ended up flunking.)
Se continuares nas festas, vais chumbar o ano.
(If you keep partying, you are going to flunk the year.)
Metade da turma chumbou no teste de história.
(Half the class flunked the history test.)
Chumbei a física pela segunda vez.
(I flunked physics for the second time.)
Summary
Use reprovar in any formal situation or when speaking Brazilian Portuguese. Use chumbar only in informal contexts within Portugal.