asquint (adv.)
early 13c., "obliquely, with a sidelong glance," of uncertain etymology; from a- (1) "on" + "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." Squint is not found in Middle English, and appears to be from this word.