Used to describe someone who is incredibly obese, to the point where it could be life threatening. First used on the today show and later popularised by popular streamer Kai Cenat.
The condition in the state of Montana where a women is not extremely overweight but they have massive arms where chub hangs off the back, a wide broad stance and slightly overweight every where else but not fat… yet
See her over there by the bar? That’s what people mean when they say a ‘Montana build’—flabby, broad, and built like they ate to much over the winter.