1. out of the blue, unanticipated, unforeseen, unlooked-for

not anticipated

Example Sentences:
'unanticipated and disconcerting lines of development'
'unforeseen circumstances'
'a virtue unlooked-for in people so full of energy'
'like a bolt out of the blue'

Synonyms

• out of the blue
• unforeseen
• unlooked-for