thinner

comparative form of thin: more thincomparativeform-of

A liquid substance used to thin the consistency of another liquid.

• Turpentine or mineral spirits can be used as a thinner for oil-based paints.

Something that thins or thins out (another thing).

• Pomegranate juice and exercise are great natural blood thinners.
• The new type of mechanical thinner allowed thinning of peach blossoms to be completed earlier.