The antonyms for the term "constant-width font" include varied-width font, proportional font, or variable pitch font. While a constant-width font has fixed character widths, a variable pitch font varies in the width of each character. Therefore, a variable pitch font is more suitable for texts that have different word lengths and character width variations.
Furthermore, proportional fonts, unlike constant-width fonts, utilize specific character widths which tailor to the letter shape's content. This makes them more suitable for lengthy drafted documents like novels, journals, magazines, and newspapers.
In summary, the antonyms of constant-width font offer various options to choose from when presenting texts in different formats or styles - which is necessary to attain proper legibility, spacing and consistency.