something or someone that is difficult to understand
что-то или кто-то, что трудно понять (chto-to ili kto-to, chto trudno ponyat)
"He’s a closed book when it comes to his personal life."
"Он — закрытая книга, когда речь идет о его личной жизни." (on zakrytaya kniga, kogda rech idet o ego lichnoy zhizni)
to be informed about something
to protect your computer system or network from attacks
by lying or misleading someone
to not worry about something until it happens
to follow your intuition or instincts
To quickly identify and learn from failures.
