Antonyms of adj convex

1 sense of convex

Sense 1
convex (vs. concave), bulging -- (curving or bulging outward)

concave (vs. convex) -- (curving inward)
        => acetabular, cotyloid, cotyloidal -- (of the cup-shaped socket that receives the head of the thigh bone)
        => biconcave, concavo-concave -- (concave on both sides)
        => boat-shaped -- (having a concave shape like a boat)
        => bowl-shaped -- (having a concave shape with an open top like a bowl)
        => bursiform, pouch-shaped, pouchlike, saclike -- (shaped like a pouch)
        => concavo-convex -- (concave on one side and convex on the other with the concavity being greater than the convexity)
        => cuplike -- (resembling the shape of a cup)
        => cupular, cupulate -- (shaped like (or supporting) a cupule)
        => dished, dish-shaped, patelliform -- (shaped like a dish or pan)
        => planoconcave -- (flat on one side and concave on the other)
        => recessed -- (resembling an alcove)
        => saucer-shaped -- (having a concave shape like a saucer)
        => umbilicate -- (depressed like a navel)
        => urn-shaped -- (having a concave shape like an urn)

Similarity of adj convex

1 sense of convex

Sense 1
convex (vs. concave), bulging -- (curving or bulging outward)
       => bell-shaped -- (having a convex shape that resembles a bell)
       => biconvex, convexo-convex, lenticular, lentiform -- (convex on both sides; shaped like a lentil)
       => broken-backed, hogged -- ((of a ship) so weakened as to sag at each end)
       => convexo-concave -- (convex on one side and concave on the other with the convexity being greater than the concavity)
       => gibbous, gibbose -- ((used of the moon) more than half full)
       => helmet-shaped -- (having the convex shape of a helmet)
       => planoconvex -- (flat on one side and convex on the other)
       => umbellate, umbel-like -- (resembling an umbel in form)
          Also See-> protrusive#1