fleer
To make a wry face in contempt, or to grin in scorn
archaic
I speak not like a dotard nor a fool, As, under privilege of age, to brag What I have done being young, or what would do, Were I not old.
LEONATO. Tush, tush, man! never fleer and jest at me:To grin with an air of civility; to leer.
archaic
In the time of popery, before the gospel came amongst us, we went to burials with weeping and wailing, as though there were no God: but since the gospel came unto us, I have heard say, that in some places they go with the corses grinning and flearing, as though they went to a bear-baiting;[…]
Where it comes from
Possibly from a Scandinavian source, compare Norwegian bokmål flire (“to giggle”), Jutish Danish flire.
Adapted from the Wiktionary entry fleer (CC BY-SA 4.0).