A shield or buckler used to protect from attack; figuratively, something that offers protection or defense.
古代の戦士は大きな盾を持って戦った。
Ancient warriors fought carrying large shields.
消防服は熱から身体を守る盾のようだ。
A firefighter's suit is like a shield that protects the body from heat.
国防は国民の盾であるべきだと主張した。
He argued that national defense should serve as a shield for the citizens.
A pretext or excuse used to avoid something; often used in the phrase 'to use ~ as a shield' (〜を盾にする).
彼は体調不良を盾にして会議を休んだ。
He used poor health as an excuse to skip the meeting.
会社は経費削減を盾にして雇用を減らしたと批判された。
The company was criticized for using cost-cutting as a pretext to reduce employment.