Their threats were nothing but popguns, lacking any real power.

popguns 是复合词，由 pop（拟声词，模仿"砰"的枪声）和 guns（枪的复数形式）组成。字面意思是"发出'砰'声的枪"，实际指"玩具枪"或"声音大但无杀伤力的枪"。 在句中用作比喻，形容"看似吓人实则无力的威胁"。