Meaning

adjective (used especially of glances) directed to one side with or as if with doubt or suspicion or envy; - Elizabeth Bowen

adverb with suspicion or disapproval

adverb with a side or oblique glance

originUnknown. Possibly from Middle English askances (“as if”), or from Old French a escone (“hidden”) or Italian a scancio (“obliquely”). Compare asquint, Middle English askoyn (“at a slant, askance”), Dutch schuin, schuins (“sideways”), schuiven (“to shove”), schuinte (“slope”).

Etymology from Wiktionary, CC BY-SA 3.0