A small, insignificant, or ridiculous person who dresses like a dandy; a contemptuous term for a fashionable but foolish young man.
From 'dandy' combined with 'prat' (slang for buttocks, used derogatorily for a fool or contemptible person), creating a doubled insult that was popular in Early Modern English.
Medieval insults were wonderfully creative—'dandyprat' appeared in Shakespeare's era and combined fashion mockery with bodily humor, which was peak comedy for 16th-century audiences.
Complete word intelligence in one call. Free tier — 50 lookups/day.