Adjective. A word hybrid between groovy and 'non-confrontational', usually uttered as an expression when one slightly beyond cool and slightly below 'infinitely freaking spectacular' is required.
It is worth noting that while this term is altogether suitable for colloquial and 'feigning interest' uses, it is unsuitable for sarcasm because it invariably sounds sincere. No, really.
Bob: Check out this Flash movie, Dave!
Dave: Hot shizz Bob, that's flippin' groovetational!
A mass of wealth so great that it can bend tax codes and pull governments out of their naturalorbits.
Guy 1 - Did you read about the candidate who was so rich he used his money to lobby for a lower tax rate for himself?
Guy 2 - Yeah. That is some gravitational wealth.