She knew from a young age that her sole 'purpose' (in life) was to be a writer. [=she knew that all she wanted (in life) was to be a writer]
We were happy to know that the money was being used 'for a good purpose'. [=for something useful, important, etc.]
There's little/no 'purpose' in restarting the process. [=there is little/no reason to start the process again]
(..) than you look. It's just words, boy, to keep us a little warmer in the night, make us feel like we've got a purpose. Come on. We've got to find these goat fuckers before night falls and they find us. - Can you read? (..)2012 TvShow: Game of Thrones Title: The Old Gods and the New Season: 2 Episode 6