under lock and key
In secure custody
Under lock and key means securely locked away, stored where unauthorized access is prevented.
The phrase emphasizes security—valuables kept under lock and key are in a safe or strongbox, not just a drawer: The documents are under lock and key.
It extends to people held in secure confinement: The suspect is under lock and key until trial.
- containmentPreventing hostile expansion
- secureProtected from harm
- maximum securityHighest-level prison classification
- confidentialityQuality of protecting secrets
- top secretHighest classification level
hidden away · classified · safeguard · keep safe · imprisonment · behind bars · key · detention · inaccessible · strongbox · safety deposit box · deadbolt · incarcerated · custody · enclosure · protect · forbidden · vault
- expressions about containmentboxed in, bottled up, hemmed in, penned in, shut in
under lock and keyaccessible
Able to be reached
up for grabs · available · open access · unrestricted · within reach
under lock and keyexposed
Out in open
unprotected · unsecured · vulnerable · unguarded · left out
under lock and keyfree
Without payment or restriction
at liberty · on the loose · free as a bird · unconfined · released
under, lock, locks, locked, locking, locker, locksmith, unlock, unlocked