Compare the compressibility of liquids and gases.
A substance is compressible only if there is enough space between particles of the substance.
Compressibility of liquids: In liquids, there is some space between the particles and is compressible, but it requires a high amount of pressure to compress them.
Compressibility of gases: In gases, there is a large space between the particles and hence is highly compressible.
Gases are more compressible than liquids. Gases are compressible because most of the volume of a gas is composed of the large amounts of empty space between the gas particles.