This is the 7952nd most frequent Spanish word.
mister
"Señor" (used as "Mister" in English).
Here, 'mister' is used colloquially in Spanish to refer to a sports coach or trainer.
El mister nos pidió que entrenáramos más fuerte esta semana.
The coach asked us to train harder this week.
In this sentence, 'mister' refers to a gentleman or a man in a formal or respectful manner.
Anoche conocí a un mister muy simpático en la reunión.
Last night, I met a very nice gentleman at the meeting.
Again, 'mister' is colloquially used to indicate the coach of a sports team.