Lockdown

3 clues
Confinement measure
Security precaution
Prison security measure
Similar answers:
Achipofftheoldblock
Aclockdidnotget
Aclockworklemon
Aclockworkorang
Aclockworkorange
Aclockworkorangecrush
Aclockworksepia
Aclockworkyellow
Acrossanddown
Adblock
Adblocker
Adown
Aflockofgs
Againsttheclock
Airlock
Airlocks
Alarmclock
Alarmclocks
Allfalldown
Allshookdown