something or someone that is difficult to understand
algo o alguien que es difícil de entender (algo o alguien que es dificil de entender)
"He’s a closed book when it comes to his personal life."
"Él es un libro cerrado cuando se trata de su vida personal." (el es un libro cerrado cuando se trata de su vida personal)
recovering from an illness or injury
being far superior to others in a particular field.
to keep an activity or process going
honest; truthful; not involved in any wrongdoing
to suddenly become very angry or lose control
Mental calmness leads to happiness and contentment.