Asquint

with an oblique glance or squint; askance; slyly; dubiously.
Historical Examples

But I know that Providence looketh not asquint, but looketh straight out, and through all men’s darkness.
Letters of Samuel Rutherford Samuel Rutherford

He,’ indicating the sun, ‘can only get at me asquint by that time, and I’m a match for him with my blue umbrella.
The Pillars of the House, Vol. I (of 2) Charlotte M. Yonge

adverb, adjective
(postpositive) with a glance from the corner of the eye, esp a furtive one
adv.

early 13c., “obliquely, with a sidelong glance,” of uncertain etymology; from a- (1) + “a word corresponding to Du. schuinte ‘slope, slant’ of the independent use of which no instances survive …” [OED]. “Middle English Dictionary” compares French équinter “cut to a point;” French dialectal (e)squintar “cast a glance, look furtively.”