Why are most liquids difficult to compress?

Liquids are difficult to compress primarily because their molecules are already packed closely together, essentially in contact with one another. Unlike gases, where molecules are far apart and move independently, the molecules in a liquid are held together by short-range attractive forces.12

Because these molecules are already in such close proximity, they resist any attempt to further shorten the distance between them. This resistance is due to strong repulsive forces that come into play when molecules are forced closer than their natural contact distance. Essentially, because there is very little "empty space" between the particles in a liquid, they cannot be squeezed into a significantly smaller volume, making them highly resistant to compression.34526