something or someone that is difficult to understand
quelque chose ou quelqu'un qui est difficile à comprendre (quelque chose ou quelqu'un qui est difficile a comprendre)
"He’s a closed book when it comes to his personal life."
"C'est un livre fermé quand il s'agit de sa vie personnelle." (c'est un livre ferme quand il s'agit de sa vie personnelle)
to gradually move up to higher positions in an organization
to go beyond the usual limits; to innovate boldly
to escape from control or restriction
to laugh very loudly or uncontrollably
Keep doing something even if it’s hard.
to formally approve something