secondguard
nounUK /ˈsekəndɡɑːd/
US /ˈsekəndɡɑːrd/
A secondguard is a helper who watches over things after the first guard.
The secondguard took over the watch when the first guard went to rest.
OTHER MEANINGS
2. A protective layer or extra shield placed behind the main one.
The secondguard on the door kept the wind out.
3. A person who supports or defends someone else as a backup.
She acted as a secondguard for her little brother at the playground.
4. In games, a second line of defense that protects the goal.
The secondguard blocked the ball before it reached the net.