To keep a secret is to tell nobody the thing you were told in confidence. It is a small weight you carry around at parties.
Keep again means hold rather than do, so the phrase describes a state you stay in for years rather than a single act. It takes from: she kept a secret from her family for a decade. The opposite is not break but let slip, give away or spill, and somebody who cannot manage it is bad at keeping secrets — a fixed and slightly fond insult.
1phrasekeep a secretTo tell nobody what you were told in confidence.
“Ask yourself first whether he can keep a secret.”
keep a secret is an act of discretion.
Practised in Common Word Pairs