From Longman Business Dictionary
stagnatestag·nate /stægˈneɪtˈstægneɪt/ verb [intransitiveI]ECONOMICS if an economy or industry stagnates, it does not grow, or it grows only very slowlyThe construction industry is stagnating and there has been a steep fall in new orders.
a stagnating economy
—stagnation noun [uncountableU]In Japan in the 1990s, a financial collapse led to economic stagnation.