1making or uttering a roar:he was greeted everywhere with roaring crowdsa swollen, roaring river
(of a fire) burning fiercely and noisily:he sat by the roaring fire
chiefly archaic behaving or living in a noisy riotous manner:a roaring boy
(of a period of time) characterized by prosperity, optimism, and excitement:the Roaring Twenties
2 informal very obviously or unequivocally the thing mentioned (used for emphasis):last week’s 70s night was a roaring success [as submodifier]:two roaring drunk firemen
do a roaring trade (or business)
informal do very good business:the cafes on the boulevard were doing a roaring tradethe food sellers were doing a roaring trade in spiced sausages
the roaring forties
stormy ocean tracts between latitudes 40° and 50° south.