This is the 14032nd most frequent Spanish word.
sustituto
Substitute.
In this sentence, 'sustituto' refers to a person serving in place of someone temporarily.
El profesor es solo un sustituto mientras el titular está enfermo.
The teacher is only a substitute while the regular one is ill.
Here, 'sustituto' refers to an alternative substance used instead of sugar.
Necesito un sustituto para el azúcar porque estoy a dieta.
I need a substitute for sugar because I'm on a diet.
In this sentence, 'sustituto' denotes something taking the place of another in fulfilling a role.