There are numerous antonyms for the word "substantialities", which refers to things that are important, tangible, and of significant value. Some antonyms to this word include trivialities, insubstantialities, emptiness, nothingness, and trivialness. These words convey the opposite meaning of "substantialities" and refer to things that are unimportant, lacking in substance, or having no tangible value. For instance, when we talk about trivialities, we refer to insignificant things that do not add any value, context, or meaning to a situation. Similarly, when we talk about nothingness or insubstantialities, we mean that something is so insignificant that it barely exists or has no real value.