English edit

Etymology edit

From over- +‎ harden.

Verb edit

overharden (third-person singular simple present overhardens, present participle overhardening, simple past and past participle overhardened)

  1. To harden too much.
    • 1661, Robert Boyle, “[Some Specimens of an Attempt to Make Chymical Experiments Useful to Illustrate the Notions of the Corpuscular Philosophy.] The History of Fluidity and Firmnesse. The Second Part. Of Firmnesse.”, in Certain Physiological Essays and Other Tracts; [], 2nd edition, London: [] Henry Herringman [], published 1668, →OCLC, page 286:
      [I]t has acquir'd ſuch a hardneſs, that being throvvn againſt the floor it vvould rebound, and vvas brittle like over-harden'd Steel.
      An adjective use.

Further reading edit