Keywords: unusual, uncommon, unexpected, inappropriate, suddenly
As a Verb or Adjective
To happen not very often, or to look quite different from everyday or normal things. English = (be) unusual, (be) uncommon.
To be surprising because you did not think it would happen. English = (be) unexpected.
To be not suitable or right for a particular occasion or use. English = (be) inappropriate.
Used alone to show that you are surprised, even sceptical, about what you have just been told. English = 'Well, I'll be...', 'Really?', 'What!?',
'Well, I've never heard that before!', and so on.
Used at the beginning of a sign sentence to mean that the action or actions that follow happen quickly and unexpectedly. English = 'Suddenly,' 'All of a sudden,' 'Out of the blue.'