Definition
'Thinned' means something has been made less dense or thick. Imagine soup that has too much broth added – it's been thinned. It can apply to both liquids and other substances. 'Thinned' is the past participle of 'thin,' meaning to make something less dense. For instance, hair can be thinned out with special scissors. It implies a reduction in thickness or density. Too much thinning can result in diminished quality or effect.