The superlative form of the adjective 'sloughy', meaning extremely soft, muddy, or swampy.
This word makes people think of very wet, soft, and dirty places.
Examples:
After the rain, the ground is at its sloughiest.
The sloughiest part of the trail is hard to walk through.
The sloughiest mud is near the river.
I don't want to walk in the sloughiest part of the field.
The sloughiest swamp is full of frogs and bugs.
The sloughiest ground is like walking on pudding.