The engine suddenly 'roared (back) to life'. [=it made the loud sound of an engine and began running well]
The audience 'roared' with laughter. [=the audience laughed loudly for a long time]
The fans were 'roaring' [=yelling and cheering loudly] after their team scored.
(..) Shame. Shame. I'm very sorry, Your Grace. Very sorry. For House Lannister! Hear me roar! For House Frey! We stand together! May we stand together through the centuries, good friends to the last. (..)2016 TvShow: Game of Thrones Title: The Winds of Winter Season: 6 Episode 10