'unpremeditated' originates from the prefix 'un-' meaning 'not' and the word 'premeditated,' which comes from Latin 'praemeditatus,' where 'prae-' meant 'before' and 'meditari' meant 'to consider.'

'premeditated' changed from the Latin word 'praemeditatus' and eventually became the modern English word 'premeditated.'

Initially, it meant 'considered beforehand,' but over time it evolved into its current meaning of 'planned in advance.'