last line of defense
noun phraseUK /lɑːst laɪn əv dɪˈfens/
US /læst laɪn əv dɪˈfens/
The very last thing that keeps you safe when everything else fails.
The goalie is the team's last line of defense.
RELATED WORDS
OTHER MEANINGS
2. The final person or group that stops an attack.
The soldiers at the gate were the last line of defense for the city.
3. A final rule or check that prevents a mistake.
The spell-checker is the last line of defense against typos.
4. The final part of a system that keeps something from breaking.
The backup generator is the last line of defense during a power outage.