Definition of "gazer"

I'll drown more sailors than the mermaid shall; / I'll slay more gazers than the basilisk;

c. 1591–1592 (date written), William Shakespeare, “The Third Part of Henry the Sixt, […]”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act II, scene ii]

Like lightening flash, that hath the gazer burned, / So did the sight thereof their sense dismay, / That backe againe upon themselves they turned, / And with their ryder ranne perforce away:

1596, Edmund Spenser, “Book V, Canto VIII”, in The Faerie Queene. […], London: […] [John Wolfe] for William Ponsonbie, page 38

Knots of gazers and gossips were collected in the churchyard, at the bridge, and at the spot where the hat and pumpkin had been found.

1820, Washington Irving, The Legend of Sleepy Hollow‎

I would observe, by the way, that it costs me nothing for curtains, for I have no gazers to shut out but the sun and moon, and I am willing that they should look in.

1854, Henry David Thoreau, Walden‎, New York: Thomas Y. Crowell & Co, published 1910, pages 86–7

Keen lemon-yellow hurts the eye in time as a prolonged and shrill trumpet-note the ear, and the gazer turns away to seek relief in blue or green.

1914, Wassily Kandinsky, chapter V, in M.T.H. Sadler, Houghton Mifflin, transl., The Art of Spiritual Harmony‎, page 49