1) to thoroughly enjoy something with Robin Williams like enthusiasm. 2) the highest possible degree of like or enjoyment.
The word jumanj was coined after a discussion on the word love. The thinkers in the room noted that love has a much heavier and deeper meaning that "the highest degree of enjoyment or like." Therefore the group of thinkers set out to come up with a word that captures the excitement and joy that comes with liking something a whole lot. Jumanj was the word that came up and due to its exotic phonetics, it was dubbed the word fit to describe a high level of enjoyment and like.