The word unforeseen means to not know in advance. It implies that a person did not anticipate an activity or thought.
Ex: The weather change was unforeseen. The storm arrived quickly, and the surprise round of hail was difficult to clear off the roads fast enough for drivers.
Ex: The outcome of the election was unforeseen by most people. The least known candidate was able to raise awareness at the last minute to win.
The prefix un-, meaning "not", can also be used to make other common words. For example, it is used to form the words undress and unavailable. The word undress means "not dressed" or "to take your clothes off". Unavailable means "not available" or "not ready for use".
Ex: Wait to undress. I know it is a restaurant bathroom and you need to change for work, but you should always demand privacy for yourself.
Ex: My brother is unavailable to help this weekend. If I do not have enough people to help me move, it is out of my control.
The word unintentional refers to something that is not done on purpose. The result of something was not intended. In this case, it is a synonym for unplanned.
Ex: If Mary insulted her, it was unintentional. As a rule, she is kind to everybody and would never try to hurt someone's feelings.
Ex: That hit was unintentional! I cannot believe the referee called a foul as if the player meant to hurt his opponent!
The prefix un-, meaning “not”, can also be used to make other common words. For example, it is used to form the words unskilled and uninterested. The word unskilled means to “not have a specific skill” or “having no training”. The word uninterested means “not interested” or “to be indifferent”.
Ex: If I graduate from university, I'll not have to worry about having an unskilled job. My education will help me get a job in business.
Ex: I am uninterested in what she has to say. We see each other in the cafeteria occasionally, but neither of us wants to start a conversation