The term validate is from the 1570s, "having force in law, legally binding," from French valide (16c.), from Latin validus "strong, effective, powerful, active," from valere "be strong."
How do you validate your business model? Revenue growth is a good way to validate your business model. Do you have enough revenue to survive? How many customers are using your product/service? How strong is your business? How effective are you? Ask many questions to validate your business model.
Disconcerting dream, awaken with a startle, mix in a nightmare