safety lock

noun pl. safeties

1. the quality or condition of being safe; freedom from danger, injury, or damage; security
2. any of certain devices for preventing an accident or an undesirable effect; specif.,
   1. a catch or locking device on a firearm that prevents it from firing
      also safety catch or safety lock
   2. Slang a condom
3. ☆ Baseball base hit
4. ☆ Football
   1. a play in which the defensive team is awarded two points as by tackling the offensive ball carrier behind the offensive team's goal line
   2. a defensive back who is primarily responsible for covering pass receivers in the middle of the defensive backfield

adjective