Stop arguing over these piffling matters; we have more important things to deal with.

piffling 是形容词，由动词 piffle（说废话、做无聊事）加上后缀 -ing 构成。piffle 本身是个拟声词，模仿无意义话语的声音。piffling 形容事物"微不足道的、琐碎的"，常带有贬义，表示不值得关注或浪费时间。