Within the sub-meaning of "literal" -- of a portrait being actually such, without exaggeration or inaccuracy. It's a comparison, not a niche. Although obviously Sargeant was influenced by the European Impressionist, his portraits are meant to convey a person's face as it actually appears, even if the stylistic approach is to soften the contrasts of light and color.
Portrait of Henry James
Sargeant tended towards a much more illustrative (literal) representation of the subject, playing down the detail, sometimes capturing character and personality in extraordinary ways, but had painted so many commissioned portraits that some of the are almost entirely illustrative.
In the other direction of more fluidity and atmospheric light control, "El Jaleo" is likely his masterpiece: