hit the nail on the head
- to be correct or accurate or exactly right
Wiktionary
verb
- To identify something exactly; to arrive at exactly the right answer.
“He hit the nail on the head when he said the problem was the thermostat.”
“"Scotte's discovery of Witchcraft dismasketh sundry egregious impostures, and in certaine principall chapters, and speciall passages, hitteth the nayle on the head with a witnesse."”