Definition of "yerk"

To doe no contriu'd mur[t]her; I lacke iniquity / Sometimes to do me ſeruice: nine or ten times, / I had thought to haue ierk'd him here, / Vnder the ribbes.

c. 1603–1604 (date written), William Shakespeare, “The Tragedie of Othello, the Moore of Venice”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act I, scene ii], page 6

Their wounded steeds […] / Yerk out their armed heels at their dead masters.

1599 (date written), William Shakespeare, “The Life of Henry the Fift”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act IV, scene vii]

Vp on a ſuddaine they together ſtart, / And driue at him as faſt as they could ding, / They flirt, they yerke, they backvvard fluce, and fling / As though the Deuill in their heeles had bin, / That to eſcape the danger he vvas in.

1627, Michaell Drayton [i.e., Michael Drayton], “The Moone-calfe”, in The Battaile of Agincourt. […], London: […] A[ugustine] M[atthews] for VVilliam Lee, […], published 1631, page 242

Imagine twenty thouſand of them breaking into the midſt of an European Army, confounding the Ranks, overturning the Carriages, battering the Warriors Faces into Mummy, by terrible Yerks from their hinder Hoofs.

1726 October 28, [Jonathan Swift], “The Author’s Veracity. His Design in Publishing this Work. […]”, in Travels into Several Remote Nations of the World. […] [Gulliver’s Travels], volume II, London: […] Benj[amin] Motte, […], part IV (A Voyage to the Houyhnhnms), page 345