simultaneous 15 antonyms and opposites of simultaneous. Adj — Happening or done at exactly the same time as something else. Synonyms for simultaneous coincident coincidental concomitant concurrent homochronous isochronous synchronal synchronical synchronous Antonyms for simultaneous sequential asynchronous metachronous antisynchronous asynchronic heterochronous polychronic uncoincidental unconcurrent noncoincident noncoincidental nonconcurrent nonisochronous nonsimultaneous nonsynchronous ← Back to the full definition of simultaneous
