Definition of "smirch"

smirch¹

/smɜː(ɹ)t͡ʃ/

noun
countable and uncountable, plural smirches
1. (archaic) Dirt, or a stain.
  Quotations
  Too often, in the years between 800 and 1050, the everyday sun declined through the smirch of flame and smoke of a monastery or town robbed and burnt.
  1998, Michael Foss, People of the First Crusade, page 6
2. (figurative, archaic) A stain on somebody's reputation.
  Quotations
  there were some business transactions which savored of dangerous speculation, if not dishonesty; and around it all lay the smirch of the Freedmen's Bank.
  2008, W. E. B. Du Bois, The Souls of Black Folk, page 33
verb
third-person singular simple present smirches, present participle smirching, simple past and past participle smirched
1. (transitive, archaic) To dirty; to make dirty.
  Quotations
  CELIA. I'll put myself in poor and mean attire, / And with a kind of umber smirch my face; / The like do you; so shall we pass along, / And never stir assailants.
  c. 1598–1600 (date written), William Shakespeare, “As You Like It”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act I, scene iii], lines 101–104
  Girls thought that by leaping over the fires without being smirched they made sure of a happy marriage.
  1911, James George Frazer, The Golden Bough, volume 10, page 108
2. (transitive, figurative, archaic) To harm the reputation of; to smear or slander.

smirch²

/smɜː(ɹ)t͡ʃ/

noun
plural smirches
1. (astronomy) A chirp of radiation power from an astronomical body that has a smeared appearance on its plot in the time-frequency plane (usually associated with massive bodies orbiting supermassive black holes)
  Quotations
  The strain h(t) produced by a smirch in LISA is given by h(t) = −-A(t)cos[(t) + φ(t)]
  2003, B. S. Sathyaprakash, BF Schutz, “Templates for stellar mass black holes falling into supermassive black holes”, in Classical and Quantum Gravity, volume 20, number 10
  By observing a smirch, LISA offers a unique opportunity to directly map the spacetime geometry around the central object and test whether or not this structure is in accordance with the expectations of general realtivity.
  2005, John M. T. Thompson, Advances in Astronomy: From the Big Bang to the Solar System, page 133