boast, exaggerate, great, broad
訏 centers on speech that stretches the truth: boasting, exaggerating, or making something sound greater or broader than it is.
訏 combines 言 (speech) with 于, which likely contributes the sound and may suggest a sense of going beyond or extending, fitting the idea of exaggerated speech.
Words (言) that go beyond (于) the truth: 訏 is speech that exaggerates and boasts.
For ク, imagine a boastful speaker whose exaggerated claims make you think 'cool story, bro' — the 'cool' cues ク while the boasting fits the meaning.