Emily Dickinson Lexicon

FLEER, v.i. [Scot. flyre, or fleyr, to make wry faces, to leer, to look surly; Ice. flyra. In D. gluuren signifies to leer, to peep; Sw. plira; Dan. plirendc, ogling, leering. This word seems to be leer, with a prefix, and leer presents probably the primary sense.]

1. To deride; to sneer; to mock; to gibe; to make a wry face in contempt, or to grin in scorn; as, to fleer and flout. Covered with an antic face, / To fleer and scorn at our solemnity. Shak.
2. To leer; to grin with an air of civility. Burton.