Steam
steam, vapor
A five letter word which means to convert into vapor is steam. It is the process of heating or boiling water and turning it into vapor.
Fog
SublimateImprovedActually, sublimate is to change from a solid to a gas while skipping the liquid state. However, the 9 letter word changing WATER into vapor is evaporate.
Vapor
steam
evaporate
evaporate
vaporize
it is the fraction of light in water vapor
evaporate, sublimate
evaporate, sublimate