Someone who is, or is doing something like a Jigger. But the person isn't considered a Jigger.
Jiggerly shouldn't be used to describe something a Jigger does, because a Jigger's a Jigger. Anything a Jigger's doing, their automatically doing Jiggerly. So it'd be like saying something that's already understood, twice.
And that just gets annoying.
Nickname given to bales of marijuana thrown overboard or out of airplanes. Origin is reportedly from members of the US Coast Guard in the area of Southern Florida.
"Base we've got some square groupers floating outside of Miami harbor."