Definition of "unlockable"

The facilities at Harvard Law School included lockable and unlockable carrels and lockable rooms. The lockable carrels and rooms were limited in number and were assigned to students by priority based on age.

1980, Commerce Clearing House, Tax court memorandum decisions: Volume 38

Casters can be swivel, rigid, lockable, or unlockable.

2003, David E. Mulcahy, John Dieltz, Order fulfillment and across the dock concepts, design operations handbook, page 172

This unlockable demo allows customers to use the full-featured product free for seven days.

1998, Brent D Heslop, David A Holzgang, HTML Publishing on the Internet

But usually when people refer to the metagame, they mean things such as unlockables or customizable features.

2012, Keith Burgun, Game Design Theory: A New Philosophy for Understanding Games, CRC Press, page 98