Most splendrous is an adjective that describes something that is very splendid or magnificent. However, there are several antonyms that can be used to describe the opposite of most splendrous. Some of the antonyms include dull, plain, ordinary, common, unremarkable, lacklustre, uninspiring, and unimpressive. These words can be used to describe something that is not magnificent or splendid in any way. For instance, a dull movie, plain outfit or unremarkable performance may not be described as most splendrous. Therefore, antonyms for most splendrous can help to communicate the opposite of something that is magnificent and brilliant.