sagging

1. To sink, in the middle, by its weight or under applied pressure, below a horizontal line or plane.

   A line or cable supported by its ends sags, even if it is tightly drawn.

2. (by extension) To lean, give way, or settle from a vertical position.

   A building may sag one way or another.

3. To lose firmness, elasticity, vigor, or a thriving state; to sink; to droop; to flag; to bend; to yield, as the mind or spirits, under the pressure of care, trouble, doubt, or the like; to be unsettled or unbalanced.
4. To loiter in walking; to idle along; to drag or droop heavily.
5. To cause to bend or give way; to load.
6. To wear one's trousers so that their top is well below the waist.

1. The act of something that sags.
2. A manner of wearing pants or shorts below the waist, revealing some or all of the underwear.

adjective

(of a person or clothes) Worn low on the waist, or wearing pants or shorts low on the waist.