The property due to which a substance abosrbs moisture and dissolves in it is called
deliquescent
Hygroscopic materials absorb moisture, but deliquescent materials absorb moisture to the extent the substance dissolves in water. Deliquescence may be considered an extreme form of hygroscopy.
Efflorescence is the migration of a salt to the surface of a porous material, where it forms a coating.
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence.