1. Very great in size (mass, weight, girth, height and/or length).
2. Extremely significant and important.
My buddy and I were walking along the railroad tracks to go fishing. We saw a freight train sitting idle on a second pair of rails. One of the boxcars had graffiti spray-painted on the side. The largest piece of graffiti read:
"People Are BIG
MACHINES ARE HEMAGA!!"
We interpretted this as meaning that a piece of machinery is much large than a human being. Even though this is not always true (e.g. person vs. blender), it was true at the time (e.g. person vs. train).
I can't read this contract; it's hemaga! (Me, when signing my mortgage)
Whales are hemaga. (Herman Melville)