The word 'squinty' is a relatively modern English formation, built upon the earlier verb 'squint'. The verb 'squint' itself likely entered Middle English from a Scandinavian source, such as the Swedish dialect word 'svincka', meaning to squint or to have a sideways glance. This root carried the core semantic idea of looking with narrowed or oblique eyes, often due to bright light or an effort to see more clearly. The productive English adjectival suffix '-y', with its ancient Germanic lineage tracing back to Proto-Germanic -igaz, was then appended to this root. The resulting adjective 'squinty' literally means "characterized by squinting" or "inclined to squint," directly describing the physical appearance or habitual action of the eyes.

Structure: squint (to look with narrowed eyes) + y (adjective-forming suffix) - squint: Likely of Scandinavian origin (cf. Swedish svincka, to squint), functioning as the core verb/root meaning to look with eyes partly closed. - y: A native English suffix (from Old English -ig), functioning to form adjectives meaning "characterized by" or "inclined to".