under lock and key

ADJECTIVE

captive

Synonyms

STRONGEST

caged enslaved imprisoned incommunicado

STRONG

bound

WEAK

confined ensnared in custody incarcerated jailed locked up penned restricted subjugated

Antonyms

WEAK

disillusioned free independent loose uninterested

ADJECTIVE

safe

Synonyms

STRONGEST

intact protected secure

STRONG

okay snug

WEAK

cherished free from danger guarded home free impervious impregnable in safety inviolable invulnerable maintained out of danger out of harm's way preserved safe and sound safeguarded sheltered shielded sitting pretty tended unassailable undamaged under one's wing unharmed unhurt uninjured unmolested unscathed unthreatened vindicated watched

Antonyms

STRONGEST

insecure unprotected

WEAK

dangerous exposed harmful incautious poisonous risky unguarded unsafe unthoughtful vulnerable

VERB

behind bars

Synonyms

WEAK

confined imprisoned in jail in prison incarcerated jailed put away serving time

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The sorrows that trouble him he keeps under lock and key.

From The Wall Street Journal • Dec. 4, 2025

Maybe we’ll find ourselves under lock and key across the street in the Eisenhower Executive Office Building.

From Salon • Nov. 7, 2025

Wirtz could provide an option on the flank, but Liverpool's wide areas appear to be under lock and key.

From BBC • Jun. 20, 2025

The acting is grounded in realism but the writing refuses to keep the characters under lock and key.

From Los Angeles Times • Apr. 28, 2025

“We’ll have the troll back under lock and key long before Captain Short is in any danger.”

From "Artemis Fowl" by Eoin Colfer