Definition - Noun - A dance move that resembles the Giant Wacky Waving Inflatable Arm Flailing Tube Man, made famous by current New England Patriot, Rob Gronkowski.
Definition - Verb - Describing the act of Gronknastiing.
Definition - Adjective - Witnessing an event that is shockingly priceless.
Gronknasti - Verb - I can't wait to hit up the club tonight and Gronknasti all over my dude bros.
Gronknasti - Adjective - Did you see see that huge dude on the dance floor flailing his arms like a Giant Wacky Waving Inflatable Arm Flailing Tube Man? That shit was Gronknasti.