"More highbrow" implies sophistication and intellectualism. Its antonyms would be words like unrefined, simple, unsophisticated, and basic. These terms suggest a lack of depth, complexity, or elegance. Other antonyms for "more highbrow" might include pedestrian, lowbrow, uncultured, or plain. These words describe things that lack the refinement or cultural significance that typically characterizes highbrow pursuits, such as fine art, classical music, or literature. Depending on the context, words like vulgar, crass, or crude might also serve as opposites to "more highbrow." Ultimately, the antonyms to "more highbrow" capture a range of qualities that are antithetical to the notion of intellectualism and cultural refinement.