To keep something secret.
Garder quelque chose secret. (Garder quelque chose secret.)
"I’ll tell you a secret, but keep it under your hat."
"Je vais te dire un secret, mais garde-le pour toi." (Je vais te dire un secret, mais **garde-le pour toi**.)
having sworn to tell the truth in court
to regain control of your emotions or behavior
to break into a system or network to gain unauthorized acces...
to hide or ignore problems instead of solving them
to not completely believe something
a perfect romantic couple