A grimalkin (also called a greymalkin) is an archaic term for a cat. The term stems from "grey" (the colour) plus "malkin", an archaic term with several meanings (a cat, a low class woman, a weakling, a mop or a name) derived from a hypocoristic form of the female name Maud. Scottish legend makes reference to the grimalkin as a faery cat that dwells in the highlands.
Nostradamus the French prophet & astrologer, 1503-1566, had a cat named Grimalkin.
Beware the Cat was published in 1570 by William Baldwin. The novel is a story of talking cats, and part of it relates the story of the Grimalkin's death. According to its editors, the story, and thus the name, originates with Baldwin in terms of being the earliest example known in print. It is also spelled Grimmalkin or Grimolochin.
A cat named Grimalkin in William Shakespeare‘s 1606 play MacBeth helped the three blind witches look into Macbeth’s future.
During the early modern period, the name grimalkin – and cats in general – became associated with the devil and witchcraft. Women tried as witches in the 16th, 17th and 18th centuries were often accused of having a familiar, frequently a grimalkin. A noted example is the familiar of one of the three witches in Macbeth.