verb / noun
sag
SAG/sˈæɡ/
To bend or sink downward under weight.
The old shelf sags under the weight of heavy books.

Etymology
Middle English saggen already described hanging unevenly or sinking down, the downward movement seen in something drooping under weight. Its earlier origin is uncertain, possibly Scandinavian or Middle Low German.
In context
the people packed in there like sardines in a can actually caused the bridge to sag.
More examples
- Snow makes the porch roof sag.
- There is a deep sag in the middle of the mattress.
- The clothesline is sagging beneath the wet towels.
Forms
sag · sags · sagged · sagging
saggy adjective — Drooping or hanging down loosely.