Nouns

(n)strabismus, squintabnormal alignment of one or both eyes
(n)squintthe act of squinting; looking with the eyes partly closed

Verbs

(v)squint, squinchcross one's eyes as if in strabismus“The children squinted so as to scare each other”
(v)squintbe cross-eyed; have a squint or strabismus
(v)squintpartly close one's eyes, as when hit by direct blinding light“The driver squinted as the sun hit his windshield”

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”