This is the 1048th most frequent Catalan word.
substituir
To replace or substitute.
Here, 'substituir' is used in the context of replacing a physical object (the lock) with another due to necessity.
Ell va haver de substituir el pany de la porta.
He had to replace the door lock.
In this sentence, 'substituir' means taking the place of someone in a functional role, typically used in sports or events.
L'entrenador ha decidit substituir el jugador lesionat.
The coach decided to substitute the injured player.
'Substituir' here indicates replacing one concept or event (a program) with another one (a movie), which often happens in broadcasting or scheduling.