[ hahr-dn-er ]

  1. a person or thing that hardens.

  2. a substance mixed with paint or other protective covering to make the finish harder or more durable.

  1. Photography. a chemical used to raise the melting point of an emulsion.

Origin of hardener

First recorded in 1605–15; harden + -er1

Words Nearby hardener

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use hardener in a sentence

  • Guet and guiv demand dhe (u) hardener, az boldly az gues and guilt.

  • A recent rival of tungsten both as a filament for lamps and hardener for steel is molybdenum.

    Creative Chemistry | Edwin E. Slosson
  • They are so cruel, without even knowing that they are so: the habit of seeing sin and suffering is such a heart-hardener.

    Records of Later Life | Frances Ann Kemble
  • She was a harmful woman, a destroyer of young tempers, a hardener of young hearts.

    Stage Confidences | Clara Morris

British Dictionary definitions for hardener


/ (ˈhɑːdə) /

  1. a person or thing that hardens

  2. a substance added to paint or varnish to increase durability

  1. an ingredient of certain adhesives and synthetic resins that accelerates or promotes setting

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012