1. A succession of detailed and relentless questions: Louis, the ring leader of the playground gang, said he felt like he had been through an inquisition after he had been to the principal's office.
2. An investigation that is harsh or even unfair: When capitalized, "The Inquisition" was an organization in the Roman Catholic Church founded in the 13th century to find, question, and sentence those who did not hold orthodox religious beliefs.

The Spanish Inquisition lasted until the 19th century and was known for its harsh punishments and use of torture.