Clinker is a material used in the production of cement, and it refers to the solid, dense residue left over after coal or other carbonaceous materials are burned. Antonyms for the word "most clinker" can include terms like clean-burning, streamlined, efficient, polished, and refined. These words indicate a high level of quality and effectiveness, which is the opposite of the rough, uneven texture of clinker. Additionally, words like modern, advanced, and innovative can also serve as antonyms for clinker, as they refer to the latest and most sophisticated technologies and processes that have replaced older, less efficient methods.