tarnish

Etymology

From Middle English ternysshen, a borrowing from Old French terniss-, stem of ternir (“to make dim, make wan”), borrowed from Frankish *darnijan (“to conceal”). Doublet of dern and darn.

noun

1. Oxidation or discoloration, especially of a decorative metal exposed to air.
   1918, Hannah Teresa Rowley, Mrs. Helen Louise (Wales) Farrell, Principles of Chemistry Applied to the Household Precipitated calcium carbonate, a very fine powdery form, is used as a basis for many tooth powders and pastes. As whiting it finds a wide use in cleaning metals of their tarnishes.

verb

1. (intransitive) To oxidize or discolor due to oxidation.
   Careful storage of silver will prevent it from tarnishing.
2. (transitive) To compromise, damage, soil, or sully.
   He is afraid that she will tarnish his reputation if he disagrees with her.
   There are normally anti-embarrassment clauses in such arrangements and, from a corporate social responsibility point of view, the upside of standing by a tarnished individual is often outweighed by the downside. March 11, 2022, David Hytner, “Chelsea are in crisis but there is no will to leave club on their knees”, in The Guardian
3. (intransitive, figurative) To lose its lustre or attraction; to become dull.
4. (copyright law) To use a sign, image, expression, etc. sufficiently close to a trademarked one that it brings disrepute to it.