to/for oneself
Quien sólo vive para sí, está muerto para los demás.
He who lives only for himself is dead to others.
Se guardan para sí mismos, se esconden en el Mercado de Marsh.
They keep to themselves, they hide in Marsh Market.
— Zootopia 2 (2025)
Pobre hombre, vaya problema que se ha creado para sí.
Poor man, what a problem he's created for himself.
— Stalker (1979)
Bruce se reía para sí mientras leía la carta.
Bruce chuckled to himself as he read the letter.