The term 'unexpected' can be described in many ways, such as COINCIDENTAL (12 letters), ADVENTITIOUS (12 letters), CONTINGENT (10 letters), UNACCUSTOMED (12 letters), ACCIDENTAL (10 letters), INSTANTANEOUS (13 letters), FLEET (5 letters), SURPRISE (8 letters), ODD (3 letters), ABRUPT (6 letters), SUDDEN (6 letters), ANOMALOUS (9 letters), and STARTLING (9 letters). These words all describe something that is not expected or anticipated, and often happens suddenly or unexpectedly. For example, something that is COINCIDENTAL is an event that occurs by chance, while something that is ADVENTITIOUS is an event that is not planned or expected. Something that is CONTINGENT is dependent on something else, while something that is UNACCUSTOMED is not familiar or usual. An ACCIDENTAL event is one that is not intended, while something that is INSTANTANEOUS happens immediately. Something that is FLEET is fleeting or passing quickly, while a SURPRISE is an unexpected event. Something that is ODD is strange or unusual, while something that is ABRUPT is SUDDEN and unexpected. Something that is SUDDEN is also unexpected, while something that is ANOMALOUS is deviating from the norm. Finally, something that is STARTLING is shocking or unexpected.