the rough side of one's tongue

uncountable

Angry words, harsh criticism.

Japanese Meaning

怒りを帯びた言葉 / 辛辣な批判

When someone is cornered, the rough side of one's tongue can come out and cut more deeply than intended.

追い詰められると、辛辣な言葉が口をついて出て、思ったよりも深く人を傷つけることがある。

Sense（1）

Angry words, harsh criticism.

But let them, if they plague thee long,

Once feel the rough side of thy tongue: