Nonsimultaneous refers to things or events that do not occur at the same time. Antonyms of nonsimultaneous would be words that signify simultaneity or synchronous occurrences. Some antonyms for nonsimultaneous are synonymous to each other, such as concurrent, coexistent, and coincidental. Others may have slightly different connotations, such as simultaneous, simultaneousness, simultaneous occurrence, and simultaneous action. Additionally, some antonyms of nonsimultaneous include synchronized, contemporaneous, synchronal, and synchronous. These words are useful for describing events, actions, or situations that happen at the same time, indicating simultaneity or synchronicity.