Infinitesimalness refers to the quality of being extremely small or tiny. Synonyms for this word include minuteness, microscopic size, atomism, and smallness. Other synonyms may include petiteness, littleness, tininess, and sub-atomic size. These words convey a sense of insignificance and importance. Infinitesimalness can also be described as something that is barely noticeable or insignificant, which makes synonyms such as insignificance, triviality, and inconsequentiality appropriate. It is important to note that while these words may have similar meanings, each one brings a slightly different connotation to the table. Therefore, it is important to choose the word that best fits the context of your sentence.