"Plummier" can be replaced by a variety of synonyms depending on the context. For example, if referring to something being heavier or more substantial, alternatives could include weightier or sturdier. When discussing the elegance or sophistication of something, options could be posher or more refined. If indicating something is more in line with expectations or standards, fitting or appropriate may be used. Alternatively, some may opt for the phrase "more plum-like" as a creative or whimsical way of replacing "plummier." Ultimately, choosing a synonym for "plummier" depends on the intended meaning and usage within a particular sentence or conversation.