Antonyms of square:
circular, round, discoidal, disclike, nutlike, spherical, moon-round, spheric, apple-shaped, wheel-like, cumuliform, pear-shaped, coccoid, globose, unwholesome, globular, indirect, roundish, unpaid, goblet-shaped, discoid, orbicular, pancake-like, moonlike, disklike, pinwheel-shaped, ringlike, ball-shaped, bulb-shaped, bulbous, barrel-shaped, global, bulblike, disc-shaped, capitate, unconventional, disk-shaped, deceitful, deceptive, dishonest, arbitrary, unconscionable, unreasonable, jaundiced, unfriendly, unsympathetic, colored, distorted, warped, biased, ex parte, inequitable, nonobjective, one-sided, partial, parti pris, partisan, prejudiced, unjust.
Examples of usage:
  1. The square is not very large; it will only take a little while to go from door to door.
    "A Vanished Hand", Sarah Doudney.
  2. I nodded, and looked him square in the eye.
    "54-40 or Fight", Emerson Hough.
  3. Let the square take ground by the right, and then advance!
    "The Green Flag", Arthur Conan Doyle.