Unexpected synonyms such as adventitious, abnormal, and abrupt. Unexpected is an adjective, and its antonyms are expected and predictable. Additionally, here are 24 synonyms, related words, and verbs for unexpected.
abnormal, abrupt, adventitious, astonishing, backasswards, chance, extraordinary, fortuitous, not bargained for, out of the blue, serendipitous, startling, sudden, surprising, unanticipated, uncommon, unforeseen, unhoped for, unlooked for, unplanned, unpredicted, without notice, and without warning.