The antonyms for the word "most splintery" can be smooth, polished, sleek, refined, and gentle. Splinters can be painful and dangerous, causing discomfort and injury to the skin. Thus the antonyms mentioned above, offer quite the opposite of what splinters represent. Smooth and polished signify being neat and well-maintained, while sleek and refined denote elegance and sophistication. Gentle, on the other hand, embodies softness and delicacy. Thus, when you think of antonyms for "most splintery," you imagine an object or surface that is free from rough edges, smooth to touch, and comfortable to handle.