Green’s Dictionary of Slang

1. to grin, to laugh in someone’s face.

1696		J. Dunton Night-Walker Nov. 15: A Wanton Flickering girl, who used with one of her Companions to eye every one that came into the Church, and observe any thing in their Dress or Deportment, that could make them matter of Mirth.
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1859		Matsell Vocabulum.

2. (US tramp) to faint or pretend to faint, to die.

1899		J. Flynt Tramping with Tramps 384: ‘I’m starvin’, father,’ I yapped, ’n’ begun to flicker. [Ibid.] 385: ‘Flicker,’ meaning to faint, comes from the flickering of a light.
1921		P. & T. Casey Gay-cat 302: Flicker—a faint; as a verb, to faint or pretend to faint.
1930		‘Dean Stiff’ Milk and Honey Route 205: Flicker – To faint or simulate fainting.
1932		F. Jennings Tramping with Tramps 212: Flickers – fainting.