mackle

/M AE1 K AH0 L/
noun
  1. 1

    A spot.

  2. 2

    A blur or an appearance of a double impression, as when the paper slips a little during printing.

verb
  1. 1

    To blur or be blurred; especially to blur or double an impression from type.

Source: https://en.wiktionary.org/wiki/mackle, https://en.wiktionary.org/wiki/macule