harsh language; sharp words
Refers to speech that is severe, cutting, or critical, often used in contexts of conflict or strong disapproval.
He got angry and hurled harsh words.
I hurt the other person with sharp words.
Compound of 険しい (けわしい, 'steep, severe, harsh') and 言葉 (ことば, 'word, language'). The phrase is straightforward and its meaning is derived from the components.