Decondensed is a term used to describe something that has been made less dense or less compact. Some synonyms for decondensed include dilute, rarefied, dispersed, thinned, attenuated, and diffused. Dilute implies that a substance has been added to water or another liquid to make it less concentrated. Rarefied means that something has been made less dense by removing gas particles. Dispersed suggests that something has been spread out or scattered. Thinned implies that something has been reduced in thickness or density. Attenuated refers to something that has been made thinner or less substantial. Finally, diffused implies that something has been spread out or dispersed over a wide area.