unpremeditated

Definitions

Not thought out or planned beforehand; spontaneous.

Done or occurring without prior deliberation or intent.

Examples

The comedian's witty remark was entirely unpremeditated, catching the audience completely off guard.

He offered an unpremeditated apology the moment he realized he had hurt her feelings.

Synonyms

spontaneous impulsive unplanned extemporaneous impromptu unintentional instinctive

Antonyms

premeditated planned deliberate calculated intentional preconceived studied