Andrei Marinescu discusses growth hacking, which is a multidisciplinary, holistic, and scalable approach to growth. It involves teams from product, design, engineering, and marketing working together using repeatable and ROI-driven tactics like A/B testing, analytics, and paid marketing to formulate hypotheses, validate ideas with MVPs, pursue traction, achieve product-market fit, and scale successfully. Some key growth tactics include creating a great product, clearly communicating the offering, understanding users, defining metrics, and focusing on engagement and retention.