(n.) One who takes advantage of circumstances\.

adventuress alpinist astronaut betting ring bettor big operator boneshaker bounder bourgeois gentilhomme brazenface cad camper cardshark cardsharp cardsharper charlatan cheat climber comers and goers commuter compulsive gambler condottiere cosmopolite crap shooter cruiser daredevil devil excursionist explorer fare fire-eater free lance gambler gamester globe-girdler globe-trotter goer gun gunman gunslinger hajji harum-scarum hazarder hellcat hero heroine hired gun hired killer hireling hotspur jet set jet-setter journeyer knave lame duck madbrain madcap margin purchaser mariner mercenary mountaineer name-dropper newly-rich nouveau riche nouveau roturier operator opportunist palmer parvenu passenger passerby pathfinder petty gambler philanderer pig in clover piker pilgrim pioneer player plunger professional killer punter rantipole rogue rubberneck rubbernecker sailor scalper scoundrel sharp sharper sharpie sightseer smart operator social climber soldier of fortune speculator sport sporting man sportsman sprout stag status seeker straphanger swashbuckler swindler tinhorn tipster tourer tourist tout trailblazer trailbreaker transient traveler trekker trickster tripper tufthunter upstart venturer viator visiting fireman voortrekker voyager voyageur wagerer wayfarer wild man world-traveler would-be gentleman