Squint

estrabismo

(look of eyes which are turned in different directions, like in strabismus)

bizquear

(to look with, or have eyes that are turned in different directions)

entornar los ojos

(to look with the eyes partly closed, as in bright sunlight)

entrecerrar los ojos

(to look with the eyes partly closed, as in bright sunlight)

mirar de soslayo

(to look or glance sideways)