To emphasize something really good or bad, depending on how it is used in a sentence. Can have several meanings and can be used as a verb or a synonym.
That dude's shirt is not da business!
My husband gave me da business last night for coming home too late.
I love her hair. It is da business!
A Shackteau is a humble, weather-beaten, structurally questionable shelter located in a spectacular or highly coveted place—Wales, Jackson Hole, Sun Valley, Crested Butte, coastal Maine, the Alps—where the building itself may be worth almost nothing, but the dirt, view, access, and mythology make it absurdly valuable.
In use:
Shackteâu - We thought it was an abandoned shed until the realtor called it a rare alpine Shackteâu with unobstructed views and listed it for $2million.