Is the word péssima the same in Brazilian and European Portuguese?

Yes

The word "péssima" is identical in both Brazilian and Continental Portuguese regarding its spelling, meaning, and grammatical function. The only difference lies in pronunciation. In Continental Portuguese, unstressed vowels (such as the "i" in péssima) are typically much more closed or "reduced" than in Brazilian Portuguese, where vowels tend to be more open and clearly articulated.

Brazilian Portuguese Examples

1. A comida do restaurante estava péssima. (The restaurant food was terrible.)
2. A internet está péssima hoje. (The internet is awful today.)
3. Essa notícia é péssima para nós. (This news is terrible for us.)
4. A bateria do meu celular está péssima. (My cell phone battery is terrible.)
5. A nota da prova foi péssima. (The exam grade was terrible.)

Continental Portuguese Examples

1. A comida do restaurante estava péssima. (The restaurant food was terrible.)
2. A net está péssima hoje. (The internet is awful today.)
3. Esta notícia é péssima para nós. (This news is terrible for us.)
4. A bateria do meu telemóvel está péssima. (My mobile phone battery is terrible.)
5. A nota do teste foi péssima. (The test grade was terrible.)