The word "deemphasize" suggests reducing the importance or significance of something. Its antonyms, therefore, refer to actions that highlight or emphasize something. The opposite of deemphasize is to emphasize or accentuate, which means to give more emphasis or importance to a particular aspect. Another antonym for deemphasize is to enhance, which signifies improving the value, quality or attractiveness of something. To underline or underscore is also an antonym of deemphasize, meaning to emphasize or highlight the importance or significance of something. Lastly, to magnify, enlarge, or amplify indicate words that refer to increasing the importance, significance or relevance of something, and therefore, antonyms for the word deemphasize.