Screw-shaped is commonly used to describe objects that resemble a helix or spiral. However, there are a myriad of antonyms for screw-shaped, depending on the specific context. These include straight, flat, round, square, octagonal, cylindrical, conical, and faceted, among others. For instance, a straight rod or a flat disc would be the antithesis of screw-shaped. Similarly, a round or cylindrical object does not possess the same helix-like structure as screw-shaped objects. The choice of antonym depends on the specific features of the object being described and the intended meaning. Ultimately, the rich diversity of language allows for a plethora of antonyms for screw-shaped, each with their own unique connotations and nuances.