Definition of "boggle"

You boggle shrewdly, every feather starts you […]

c. 1604–1605 (date written), William Shakespeare, “All’s Well, that Ends Well”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act V, scene iii], line 232

Do by thy soul, when thou findest it shy of such meditations, as wee do by our horses, that are given to boggle and start when wee ride them; When they fly back, and start at anything in the way, we do not yield to their fear, and go back (that will make them worse another time) but wee ride them up close to that they are afraid of, and so in time break them of that ill quality.

1665, Craddock, the elder, chapter XX, in Knowledge and Practice: or, A Plain Discourse of the Chief Things Necessary ... to Salvation, page 499

He boggled at arranging for bread to be left daily at some place within easy walking distance, but let that go.

1938, Norman Lindsay, Age of Consent, 1st Australian edition, Sydney, N.S.W.: Ure Smith, published 1962, page 18

[…] we start and boggle at what is unusual: and like the Fox in the fable at his first view of the Lyon, we cannot endure the sight of the Bug-bear, Novelty.

1661, Joseph Glanvill, chapter 14, in The Vanity of Dogmatizing‎, London: Henry Eversden, page 131

They are best qualified to thrive in [this world] […] whose designs all tend to their own private advantage, without any regard to the publick, or to the good of others; who can use any means conducible to such designs, bogling at nothing which serveth their purpose […]

1685, Isaac Barrow, Of Contentment, Patience and Resignation to the Will of God. Several Sermons‎, London: Brabazon Aylmer, Sermon 4, pp. 127-128

From the tenour of your last letter however, I am led to imagine, that you have formed some new attachment.—If it be so, let me earnestly request you to see me once more, and immediately. This is the only proof I require of the friendship you profess for me. I will then decide, since you boggle about a mere form.

1795, Mary Wollstonecraft, letter to Gilbert Imlay dated 4 October, 1795, in Mary Wollstonecraft: Letters to Imlay, London: Kegan Paul, 1879, p. 182

My imagination boggled at the punishment I would deserve […]

1969, Maya Angelou, chapter 15, in I Know Why the Caged Bird Sings‎, New York: Bantam, published 1971, page 82

I would be loth to exchange consciences with them, and boggle so with God Almighty; but these men by a new kind of Metaphysick have found out a way to abstract the Person of the King from his Office to make his Soveraigntie a kinde of Platonick Idea hovering in the aire, while they visibly attempt to assail and destroy his person […]

1643, James Howell, The True Informer‎, London, page 32