Adjectives

(s)askance, askant, asquint, squint, squint-eyed, squinty, sidelong(used especially of glances) directed to one side with or as if with doubt or suspicion or envy“her eyes with their misted askance look” (Elizabeth Bowen), “sidelong glances”

Adverbs

(r)askancewith suspicion or disapproval“he looked askance at the offer”
(r)askancewith a side or oblique glance“did not quite turn all the way back but looked askance at me with her dark eyes”