Unplanned (adjective)

Not planned or scheduled.

Origin:

The word "unplanned" is a combination of the prefix "un-" meaning not, and the word "planned" which means to make a plan or schedule. together it means not planned or scheduled.

Examples:

1. The company had to deal with an unplanned expense and had to cut costs.
2. The meeting was unplanned and was called on short notice.
3. He took an unplanned trip to visit his family.
4. She had an unplanned pregnancy and had to make some difficult decisions.
5. The concert was an unplanned success and attracted a large crowd.