The Collaborative International Dictionary of English v.0.48:

Squint \Squint\, v. i. [imp. & p. p. Squinted; p. pr. & vb. n.
   Squinting.]
   1. To see or look obliquely, asquint, or awry, or with a
      furtive glance.
      [1913 Webster]

            Some can squint when they will.       --Bacon.
      [1913 Webster]

   2. (Med.) To have the axes of the eyes not coincident; to be
      cross-eyed.
      [1913 Webster]

   3. To deviate from a true line; to run obliquely.
      [1913 Webster]

   4. To have an indirect bearing, reference, or implication; to
      have an allusion to, or inclination towards, something.

            Yet if the following sentence means anything, it is
            a squinting toward hypnotism.         --The Forum.
      [Webster 1913 Suppl.]

   5. To look with the eyes partly closed.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Squint \Squint\ (skw[i^]nt), a. [Cf. D. schuinte a slope,
   schuin, schuinsch, sloping, oblique, schuins slopingly. Cf.
   Askant, Askance, Asquint.]
   1. Looking obliquely. Specifically: (Med.), not having the
      optic axes coincident; -- said of the eyes. See Squint,
      n., 2.
      [1913 Webster]

   2. Fig.: Looking askance. "Squint suspicion." --Milton.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Squint \Squint\, v. t.
   1. To turn to an oblique position; to direct obliquely; as,
      to squint an eye.
      [1913 Webster]

   2. To cause to look with noncoincident optic axes.
      [1913 Webster]

            He . . . squints the eye, and makes the harelid.
                                                  --Shak.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Squint \Squint\, n.
   1. The act or habit of squinting.
      [1913 Webster]

   2. (Med.) A want of coincidence of the axes of the eyes;
      strabismus.
      [1913 Webster]

   3. (Arch.) Same as Hagioscope.
      [1913 Webster]

WordNet (r) 3.0 (2006):

squint
    adj 1: (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" [syn: askance, askant, asquint, squint,
           squint-eyed, squinty, sidelong]
    n 1: abnormal alignment of one or both eyes [syn: strabismus,
         squint]
    2: the act of squinting; looking with the eyes partly closed
    v 1: cross one's eyes as if in strabismus; "The children
         squinted so as to scare each other" [syn: squint,
         squinch]
    2: be cross-eyed; have a squint or strabismus
    3: partly close one's eyes, as when hit by direct blinding
       light; "The driver squinted as the sun hit his windshield"

Moby Thesaurus II by Grady Ward, 1.0:

39 Moby Thesaurus words for "squint":
   aberration, cast, circuitousness, cock the eye,
   convergent strabismus, cross-eye, cross-eyedness, crosswiseness,
   declination, deflection, deflexure, deviance, deviation,
   deviousness, diagonality, digression, divagation, divergence,
   esotropia, excursion, exotropia, goggle, heterotropia, indirection,
   indirectness, look askance, look asquint, nonconformity,
   obliqueness, obliquity, skew, skewness, squinch, squint the eye,
   strabismus, transverseness, upward strabismus, vagary, walleye