A meddlesome sort is someone who interferes in the affairs of others. A tamperer is someone who meddles with something, often without permission or knowledge. A YENTA is a gossipy person who spreads rumors and meddles in the affairs of others. A SNOOP is someone who investigates or pokes around in other people's business. All of these terms describe someone who is nosy and intrusive, and who meddles in the affairs of others.