I'm Confused

In the past couple years, I have noticed a new buzz word...'arguably'. Like, that amaretto cheesecake is arguably the best cheesecake in the world. I was going to post the recipe but I'm not sure if it's good or not. Does 'arguably' mean that one could argue for or against it being the best cheesecake in the world? If one would say "it is inarguably the best cheesecake in the world" then I would not have any doubts...as there would be no argument.

Maybe I don't really need to deal with this right now as I am still trying to get my head around 'flammable' and 'inflammable'.