The word adventurer was initially synonymous with gambling. The gambler would yell out “Adventure!” for help at the roulette table much as a modern gambler might yell “Come on, Seven!” at craps.
To be an adventurer was to be without responsibility or care. Quite often ‘adventurer’ was hurled as an insult.
Jonathan Swift’s Gulliver’s Travels (1726) spun adventure on its head, using the word to imply bravery and daring. Captain James Cook, sailing 40 years later, would become synonymous with the word, now often meaning one imbued with courage and class.
*Gleaned from Martin Dugard’s Farther Than Any Man: The Rise and Fall of Captain James Cook.